''Club'' is an English word with multiple meanings. It may refer to:
An association of people for social, recreational, political, or other purposes, such as a [[social club]], [[sports club]], or professional organization (see [[#Social and organizational uses|Social and organizational uses]]).
A type of [[nightclub]] or venue for entertainment and nightlife (see [[#Entertainment and media uses|Entertainment and media uses]]).
A [[club (weapon)|blunt weapon]] or a [[golf club]] used in sport (see [[#Physical objects and tools|Physical objects and tools]]).
The [[suit of clubs]] in playing cards or a [[club sandwich|sandwich]] and [[club soda|carbonated beverage]] (see [[#Culinary uses|Culinary uses]]).
A [[club set]] in mathematics or the [[clubsuit|clubs suit symbol]] (see [[#Mathematical uses|Mathematical uses]]).
Commercial entities like [[Club Med]] resorts or [[Sam's Club]] stores (see [[#Commercial and brand uses|Commercial and brand uses]]).
Other specialized uses, such as a [[club good]] in economics or a structure in [[club (anatomy)|anatomy]] (see [[#Scientific and other uses|Scientific and other uses]]).
The social and organizational sense of "club" originated in 17th-century England, where groups met in taverns for shared interests, evolving from informal gatherings to formal associations.[1] In the United States, clubs became prominent in the 19th century as hubs for networking and influence.[2]
Social and organizational uses
Social club
A social club is a voluntary association formed by individuals who join together to pursue shared interests, such as discussion, hobbies, recreation, or networking, typically involving membership fees, regular meetings, and organized activities for socialinteraction and mutual support.[3][4] These groups emphasize non-competitive bonding and community building, distinguishing them from more structured organizations focused on professional or athletic pursuits.The origins of social clubs trace back to 17th- and 18th-century Europe, particularly in England, where coffeehouses in London served as informal gathering spots for intellectuals, merchants, and politicians to debate ideas and socialize, evolving into more formalized private members' clubs by the early 19th century.[5][6] A prominent example is the Reform Club in London, established in 1836 to support political reformers advocating for expanded voting rights under the Great Reform Act of 1832, providing a dedicated space for dining, libraries, and discourse among members.[7]Social clubs encompass various types tailored to participants' preferences. Country clubs offer recreational amenities like dining halls, gardens, and social events, often in suburban or rural settings to foster leisure and networking among members.[8] Service clubs, such as Rotary International—founded in 1905 by attorney Paul P. Harris in Chicago to promote ethical business practices and community service—focus on humanitarian efforts, including local projects and global initiatives like polio eradication.[9] Hobby clubs, exemplified by book clubs, bring people together periodically to discuss literature, share insights, and build friendships around reading.[10]In the modern era, social clubs have adapted to digital advancements, particularly after 2020, with the rise of online platforms enabling virtual gatherings for remote members, such as Discord-based hobby groups or Zoom-hosted discussion circles that maintain social connections amid global disruptions like the COVID-19 pandemic.[11][12] This evolution has also spurred growth in inclusive clubs catering to marginalized groups, providing safe spaces for underrepresented communities to network and support one another, reflecting broader societal shifts toward diversity and accessibility.[13]
Sports club
A sports club is an association of individuals formed to promote and facilitate participation in athletic activities, such as soccer, tennis, or gymnastics, typically through organized training, competitions, and events.[14] These clubs often field teams at various levels, ranging from local amateur groups to professional squads that compete in national and international leagues, while cultivating dedicated fan bases that support their activities.[15]The historical development of sports clubs traces back to the 19th century, when formalized athletic associations emerged to standardize rules and organize competitions. In England, the Football Association was established in 1863 to govern the sport of association football, laying the groundwork for the creation of numerous clubs that followed its codified rules.[16] This led to the founding of prominent clubs like Manchester United in 1878, originally as Newton Heath L&YR Football Club by railway workers, which evolved into one of the world's most successful professional teams.[17]Sports clubs are structured as either amateur or professional entities, with amateur clubs emphasizing community involvement and non-paid participation, often run by volunteers, while professional clubs employ full-time athletes, coaches, and staff to compete at elite levels.[18] Governance occurs through international bodies like FIFA, which oversees 211 member associations worldwide as of 2025, indirectly regulating thousands of affiliated clubs via national federations.[19] Many clubs also feature organized fan supporter groups, such as ultras, which are passionate collectives that enhance match atmospheres through choreography, chants, and displays, though they can sometimes face scrutiny for occasional unruly behavior.[20]Economically, sports clubs generate revenue primarily from ticket sales, broadcasting rights, merchandise, and sponsorships, enabling them to sustain operations and invest in talent. For instance, Real Madrid reported revenues of €1.073 billion for the 2023-24 season, excluding player transfers, marking a 27% increase from the prior year and highlighting the financial scale of top-tier clubs.[21] Recent trends indicate a surge in women's sports clubs, driven by increased investment and visibility, with female participation in organized sports showing substantial growth—such as a 4.5 times faster revenue expansion in women's sports compared to men's from 2022 to 2024, reflecting broader rises in involvement since 2020.[22]
Entertainment and media uses
Nightclub
A nightclub is an entertainment venue licensed for the sale and supply of alcohol, typically operating late into the night or early morning, where patrons engage in dancing, socializing, and listening to music performed by disc jockeys (DJs) or live acts. These establishments emerged in the United States during the Prohibition era (1920–1933), evolving from illegal speakeasies—hidden bars that served alcohol covertly and often featured jazz music and dancing to evade law enforcement. After the repeal of Prohibition with the 21st Amendment in 1933, many speakeasies transitioned into legitimate, licensed nightclubs, establishing the modern model of controlled nightlife venues.[23][24]The post-World War II period marked a significant boom in nightclub culture, particularly in urban centers like New York City, where venues began emphasizing themed music and extravagant atmospheres. A pivotal example is Studio 54, which operated from 1977 to 1980 and became an iconic disco nightclub, attracting celebrities and influencing global nightlife by blending high fashion, inclusive partying, and theatrical performances that redefined club exclusivity and spectacle. This era's innovations spread internationally, contributing to the proliferation of nightclubs; by 2025, thousands operate across Europe, though the sector has faced declines in some regions due to economic pressures and regulatory changes, with the UK alone reporting 787 venues in 2024, down from 1,700 in 2013.[25][26][27]Key operational features of nightclubs include cover charges—an entry fee collected at the door to manage crowds and fund entertainment, often ranging from $5 to $20 depending on the event—and themed nights that attract specific demographics, such as electronic dance music (EDM) events featuring guest DJs or retro disco revivals. Safety regulations have evolved to prioritize patron protection, with the UK's Licensing Act 2003 mandating conditions for preventing crime, ensuring public safety, and protecting children from harm; post-2010 updates, including the 2010 mandatory licensing conditions order, introduced stricter age verification and measures to promote responsible alcohol service amid rising concerns over violence and overcrowding in the 2010s.[28][29][30]Nightclubs have profoundly shaped popular music genres, serving as incubators for disco in the 1970s, house music emerging from Chicago's underground scenes in the 1980s, and rave culture in the late 1980s and 1990s, where electronic beats fostered communal, euphoric experiences often tied to countercultural movements. Economically, the global nightclub industry generated approximately $25.4 billion in revenue in 2024, reflecting its role as a vibrant sector within broader nightlife markets despite challenges like the COVID-19 pandemic. In recent years, adaptations to digital platforms have led to hybrid virtual nightclubs, exemplified by the Clubhouse app, launched in March 2020 and peaking in popularity in 2021 with over 10 million weekly active users engaging in live audio "rooms" that mimic in-person socializing and music discussions.[31][32][33][34]
Club in arts and media
In various artistic expressions, the concept of a "club" often represents exclusive social circles, underground communities, or spaces for rebellion and camaraderie, serving as a metaphor for human connection, hierarchy, and cultural shifts. This theme permeates film, literature, music, television, video games, and emerging digital media, where clubs symbolize both escape and confrontation with societal norms.One seminal example in cinema is Fight Club (1999), directed by David Fincher and adapted from Chuck Palahniuk's 1996 novel of the same name. The film follows an insomniac office worker who forms an underground fight club with a charismatic soap salesman, critiquing consumerism, toxic masculinity, and alienation in modern society through escalating acts of anarchy.[35] Its cult status stems from its raw exploration of male identity crises and anti-establishment violence, influencing subsequent media on subversive groups.[36]In literature, Takis Würger's novelThe Club (2017) centers on an elite, all-male dining society at Cambridge University, where a young German protagonist infiltrates the group to expose its rituals of privilege and moral ambiguity. The story examines themes of class, gender exclusivity, and ethical compromise within insular academic clubs, drawing from real traditions at British universities.[37] Würger's narrative highlights the seductive yet corrosive power of such secretive enclaves, blending thriller elements with social commentary.[38]Music has long drawn from club culture, with subgenres evolving from the 1970s disco era, which originated in urban nightlife scenes blending funk, soul, and electronic beats for communal dancing in underground venues.[39] This foundation influenced later club-oriented works, such as Scissor Sisters' self-titled debut album (2004), a glam rock and nu-disco collection evoking vibrant club atmospheres through tracks like "Take Your Mama" and "I Don't Feel Like Dancin'."[40] Songs referencing club scenes, including Katy Perry's "California Gurls" (2010) with its playful nods to carefree partying, further capture the energetic, escapist vibe of nightlife.[41] Other notable examples include Lady Gaga's "Just Dance" (2008), which directly celebrates losing oneself in club rhythms as a form of liberation.[42]Television adaptations of club themes include the Mexican series Club de Cuervos (2015–2019), a Netflix comedy-drama satirizing sibling rivalry and corruption within a family-owned soccer club in a fictional town. Spanning four seasons, it portrays the chaotic power struggles and absurdities of club management, blending humor with critiques of machismo and institutional dysfunction in Latin American sports culture.[43]Video games have also embraced club motifs for social simulation, as seen in Club Penguin (2005–2017), a massively multiplayer online game where players embodied penguins in a virtual island community, engaging in minigames, chats, and events mimicking exclusive club activities like parties and adventures. Developed by Club Penguin Entertainment, it fostered kid-friendly social interactions until its shutdown, amassing millions of users and spawning merchandise.[44]Since 2023, digital media has expanded club concepts into immersive formats, with podcasts like those on the Clubhouse audio platform exploring social dynamics in virtual group settings through real-time discussions on community building and exclusion.[45] In virtual reality, platforms such as VRChat have popularized user-created "virtual clubs"—persistent social spaces for hangouts, karaoke, and role-playing—that simulate club exclusivity and interaction, experiencing 30% user growth in 2024 to over 130,000 concurrent participants by early 2025.[46][47] These VR environments highlight emerging trends in metaverse social media, where clubs evolve from physical to digital realms for global connectivity.[48]
Physical objects and tools
Club (weapon)
A club is a simple blunt weapon consisting of a short, heavy stick or rigid tool, typically made of wood and often weighted at one end to increase impact force. The term derives from the Old Norse "klubba," meaning a thick stick or cudgel, entering English around 1200 CE as a description of a handheld striking implement.The club's historical use dates to prehistory, with evidence of its application inferred from blunt force trauma on human remains, such as a 33,000-year-old skull from Romania showing signs of repeated blows consistent with a club-like object.[49] Actual preserved examples appear later in the Neolithic period, including the 5,500-year-old Thames beater wooden club unearthed from the River Thames in England, which experimental archaeology confirms could inflict lethal cranial fractures.[50] By the medieval era, the club evolved into more specialized forms like the mace, a metal-headed variant effective against armored opponents in European warfare from the 12th century onward.[51]Various types of clubs have emerged across cultures, including simple wooden staffs for hunting and combat, Non-Western examples include the African knobkerrie, a knob-headed wooden club employed by Zulu and other southern African groups for throwing, parrying, and striking in warfare and ceremonies.[52] In modern contexts, police batons such as the ASP expandable model, introduced in the 1970s, serve as telescoping clubs for non-lethal restraint.[53]The club holds cultural significance in mythology and warfare, exemplified by Heracles' olive-wood club in Greek lore, wielded to stun the Nemean Lion during his first labor around the 8th century BCE accounts.[54] As of 2025, clubs and batons are legal for self-defense in 86% of U.S. states and the District of Columbia (44 out of 51 jurisdictions), where they may be carried for protection but often restricted in concealed or urban settings to prevent misuse.[55] This primitive tool's legacy persists in contemporary self-defense, distinct from recreational derivatives like the golf club.
Golf club
A golf club is a specialized implement used in the sport of golf to strike a ball toward a target, consisting of a long, narrow shaft connected to a clubhead at one end and fitted with a grip at the other. The clubhead's design varies to suit different shots, broadly categorized into woods (for long-distance strikes), irons (for controlled approach shots), and putters (for rolling the ball on the green). These components must conform to the Rules of Golf, jointly administered by The R&A and the United States Golf Association (USGA), with the earliest standardization occurring in 1744 when the Gentlemen Golfers of Leith drafted the first 13 rules for organized play at Leith Links in Scotland.[56][57][58]The historical evolution of golf clubs began in 15th-century Scotland, where early handmade wooden clubs—crafted from local materials like beech or ash—were used with primitive balls, transitioning to featherie balls (leather spheres stuffed with boiled feathers) by the 17th century for better flight. In 1826, Scottish clubmaker Robert Forgan introduced hickory shafts imported from America, which became the industry standard through the late 19th and early 20th centuries due to their strength and flexibility, enabling greater distance and control. Post-1990s innovations shifted to metal alloys, with titanium heads revolutionizing club design by reducing weight while increasing clubhead size and forgiveness, allowing for higher ball speeds and straighter shots.[59][60][61]Golf clubs are classified by type and purpose, with drivers featuring low lofts (typically 8–12 degrees) to maximize distance from the tee, often exceeding 250 yards for skilled players. Irons are numbered from 1 (least loft, longest shots) to 9 (higher loft, shorter approaches), providing versatility for mid-range play on the fairway or rough. Wedges extend this with even greater lofts, such as the sand wedge at 54–58 degrees for escaping bunkers or executing high, soft-landing chips around the green.[62][63][64]Technical specifications enhance performance customization, with shaft flex ranging from extra stiff (for high swing speeds over 105 mph) to regular (for moderate speeds of 85–95 mph), influencing ball trajectory and distance. Grips, typically made from durable rubber compounds or synthetic leather, provide traction and shockabsorption, often textured for varied weather conditions. The global golf club market reached a value of USD 4.05 billion in 2024, reflecting steady demand driven by recreational growth and equipment upgrades.[65][66][67]Recent innovations focus on adjustability and sustainability, exemplified by the TaylorMade SLDR driver introduced in 2013, which featured a movable hosel system allowing up to 1.5 degrees of loft adjustment and a sliding weight for customizable center of gravity to optimize spin and launch. By 2025, manufacturers are integrating eco-friendly materials, including recycled metals for shafts and bamboo composites in clubheads and grips, to reduce environmental impact while maintaining performance standards.[68][69][70]
Suit of clubs
The suit of clubs is one of the four suits in a standard 52-card deck of playing cards, represented by a black trefoil or three-leaf clover symbol (♣) that evokes clovers and is often linked to themes of agriculture and rural life. This suit originated in 15th-century Europe, evolving from the Latin suits used in Italian tarocchi (tarot) decks, where it corresponded to batons or wooden clubs symbolizing staves or tools of labor.[71][72]The symbolism of the clubs suit derives from the French term "trèfle," meaning clover, and it is commonly associated with the earth element, representing growth, fertility, and the peasantry or agricultural class in medieval society. In cartomancy, a form of divination using playing cards, the suit signifies opportunity, action, physical labor, and positive developments such as luck or expansion, often tied to summertime and the common person's endeavors.[73][74][75]In card games, the suit of clubs plays a key role in determining hand strength and gameplay mechanics; for instance, in poker, a club flush consists of five cards all of the clubs suit, ranking equally with other flushes but distinguished by its black color. In bridge, clubs is the lowest-ranking suit for bidding and trump purposes, below diamonds, hearts, and spades, requiring players to follow suit when possible. Solitaire variants, such as Klondike, use clubs for building descending sequences in alternating colors, emphasizing strategic suit matching. Across many trick-taking and ranking systems, clubs holds the lowest precedence among the black suits, subordinate to spades.[75][76]Historical variants of playing card suits demonstrate regional adaptations; in traditional German-suited decks, common since the 15th century, the clubs position is occupied by acorns (Eicheln), alongside leaves, hearts, and bells, reflecting local flora and simplifying production for games like Skat. Since the 1800s, when mass printing revolutionized card manufacturing, the United States Playing Card Company alone has produced over 100 million decks annually, contributing to billions of standard decks worldwide that include the clubs suit.[77]In contemporary digital card games, such as online platforms for poker, bridge, and solitaire, the clubs suit retains its traditional form and function, enabling virtual play with standard deck simulations.[78]
Culinary uses
Club sandwich
The club sandwich, also known as the clubhouse sandwich, is a classic American triple-decker sandwich typically composed of three slices of toasted bread layered with sliced cooked poultry such as turkey or chicken, crispy fried bacon, fresh lettuce, ripe tomato slices, and mayonnaise.[79] This combination creates a hearty, balanced bite with contrasting textures of crunchy toast, crisp vegetables, and tender proteins. Variations may substitute ham for poultry or adjust seasonings, but the core elements remain consistent across traditional preparations.[80]The sandwich's origins trace back to the late 19th century, with the most widely accepted theory attributing its invention to the Saratoga Club-House in Saratoga Springs, New York, around 1894, where it was created as a quick meal for gamblers and club members.[79] An alternative claim points to the Union Club of New York City as the birthplace, though both highlight its emergence in elite social clubs.[81] It gained widespread popularity in the 1920s among country clubs and restaurants, becoming a staple in upscale dining settings before spreading to casual eateries.[82] Vegetarian adaptations, such as replacing poultry with marinated tofu or tempeh, have emerged to accommodate plant-based diets while preserving the layered structure.[83] Open-faced versions, using fewer bread slices for a lighter presentation, also appear in modern recipes.[84]Preparation involves assembling the layers sequentially: the first slice of toasted bread is spread with mayonnaise and topped with poultry and bacon, followed by a second slice with lettuce and tomato, and finished with a third slice. Toothpicks are traditionally inserted through the layers to secure the sandwich before cutting it into quarters or triangles for easy handling.[85] A standard serving provides approximately 700 calories and is notably high in protein, often exceeding 40 grams, making it a filling option for lunch.[86]The club sandwich has spread globally, inspiring adaptations like the Japanese katsu club, which incorporates breaded and fried cutlets with tonkatsu sauce alongside traditional fillings.[87] In the United States, it remains a diner classic, frequently featured on menus for its versatility and appeal.[88] Post-2020, amid a wellness boom emphasizing nutrient-dense foods, healthier iterations have incorporated avocado for added healthy fats and creaminess, reducing reliance on mayonnaise. As of 2025, plant-based versions using seitan or jackfruit have gained popularity in response to rising vegan demand.[89][90]
Club soda
Club soda is a type of carbonated water that has been infused with carbon dioxide under pressure and enhanced with added minerals such as sodium bicarbonate, sodium chloride, potassium sulfate, and disodium phosphate to mimic the mineral content of natural spring water.[91] These minerals contribute to a slightly salty taste and improved effervescence, distinguishing it from plain carbonated water. The pH of club soda typically ranges from 5 to 6 due to the formation of carbonic acid from the dissolved CO2, making it mildly acidic.[92] The term "club soda" originated in the late 19th century, with the first trademark registered in 1877 by the Irish company Cantrell & Cochrane, named after the exclusive Kildare Street Club in Dublin where it was initially served to members.[93]The history of club soda traces back to the invention of carbonated water by English chemist Joseph Priestley in 1772, who developed a method to infuse water with CO2 using a vat of fermenting beer.[94] In 1783, Swiss-German entrepreneur Jacob Schweppe founded a company in Geneva to produce and bottle mineral waters, laying the groundwork for commercial carbonation; Schweppes remains a dominant brand today.[95] A key advancement occurred in 1832 when New York inventor John Matthews patented an efficient apparatus for charging water with CO2, enabling cost-effective production and the rise of soda fountains in the United States.[96] By 2025, the global sparkling water market, which includes club soda, is projected to be valued at USD 47.75 billion, driven by demand for low-calorie beverages.[97]Club soda is widely used as a mixer in cocktails, providing fizz and dilution without adding sweetness or flavor, as seen in drinks like the whiskey highball or Tom Collins.[98] Its neutral profile makes it versatile for enhancing spirits while maintaining balance. Variations include seltzer water, which is simply carbonated water without added minerals, offering a cleaner taste; and tonic water, which incorporates quinine from cinchona bark for bitterness, along with sugar or sweeteners, primarily used in gin and tonics.[98] Health-wise, club soda supports hydration as a sugar-free, calorie-free alternative to sugary sodas, potentially aiding digestion due to its mild acidity, though excessive consumption may affect tooth enamel.[92]In recent years, flavored club sodas have emerged as a trend, with launches like cucumber-infused varieties in 2024 appealing to consumers seeking subtle, natural tastes without artificial additives.[99] These innovations expand its role beyond mixers into standalone refreshments, aligning with growing preferences for functional, low-sugar options. As of 2025, club soda has seen increased use in culinary applications, such as lightening batters for tempura or incorporating into zero-proof mocktails amid the rise of mindful drinking.[100]
Mathematical uses
Club set
In set theory, a club set (short for closed unbounded set) is a subset C \subseteq \kappa of a limit ordinal \kappa that is both closed and unbounded in \kappa. Formally, C is closed if for every \alpha < \kappa such that \sup(C \cap \alpha) = \alpha > 0, it follows that \alpha \in C; C is unbounded if \sup C = \kappa.[101]The concept of club sets became prominent in set theory in the 1970s, following work by Thomas Jech and Donald Kueker.[102] These sets have since become fundamental in advanced areas such as forcing axioms and large cardinal hypotheses, providing a framework for understanding "large" subsets of ordinals with specific closureproperties.[103]Key properties of club sets include that if \kappa is regular, then the intersection of fewer than \kappa many club subsets of \kappa is again a club set.[101] Club sets underpin stationary set theory, where a subset S \subseteq \kappa is stationary if it intersects every club set in \kappa; Fodor's lemma exemplifies their utility, asserting that any regressive function on a stationarysubset of a regular \kappa is constant on some stationarysubset.[104]Representative examples include the set of all limit ordinals below \kappa, which forms a club in \kappa, and the set of ordinals of cofinality \omega in \omega_2, which is stationary but not club. Club sets feature prominently in proofs of consistency results, such as the relative consistency of V = L with certain large cardinals, where definable club sets enable the construction of diamond sequences that anticipate subsets of stationary sets.[105]Recent developments link club sets to inner model theory through club guessing principles, which refine diamond-like guessing via sequences of clubs; for instance, Inamdar and Rinot (2025) provide a toolbox of club guessing ideals to derive ZFC-provable bounds on cardinal arithmetic without additional axioms.[106]
Clubsuit
In set theory, the clubsuit principle, denoted \clubsuit_\kappa for an uncountable regular cardinal \kappa, asserts the existence of a sequence \langle C_\alpha \mid \alpha < \kappa \rangle consisting of club subsets of \alpha such that for every club D \subseteq \kappa, there is a closed unbounded set E \subseteq \kappa with C_\alpha \subseteq D \cap \alpha for all \alpha \in E. This principle provides a combinatorial tool for analyzing filters on club sets, building on the foundational concept of club sets as closed and unbounded subsets of ordinals. It enables the construction of coherent sequences that "guess" initial segments of arbitrary clubs along a club, facilitating proofs in infinitary combinatorics.[107]Introduced by Jack Silver in 1971, \clubsuit_\kappa emerged as a refinement related to Jensen's diamond principle \diamond_\kappa, which similarly guesses subsets but with stationary accuracy rather than club-wise.[108] Unlike \diamond_\kappa, which requires a sequence guessing every subset A \subseteq \kappa on a stationary set, \clubsuit_\kappa focuses specifically on clubs and is strictly weaker, as its failure does not imply the failure of \diamond_\kappa.\clubsuit_\kappa implies key consequences such as stationary reflection, where stationary sets reflect to smaller ordinals under certain conditions, but it does not entail full reflection principles. In model theory, it plays a role in investigations of Vopěnka's principle, a large cardinalaxiom asserting that no class of structures is elementarily embeddable into another without proper class many embeddings, by providing combinatorial control over embeddings in forcing extensions. Regarding consistency strength, \clubsuit_\kappa holds in Gödel's constructible universe L, where diamond principles are provable from V=L. Conversely, its negation is consistent relative to the existence of Woodin cardinals, as shown through forcing over models with supercompact or stronger assumptions that destroy such guessing sequences.[107]Post-2010 developments in PCF (possible cofinalities) theory have leveraged \clubsuit_\kappa for advanced applications, addressing gaps in earlier analyses by establishing precise bounds on ordinal-valued functions and characterizing stationary sets within the approachability ideal I[\lambda]. For instance, it has been used to derive exact upper bounds for functions in pcf generators and to show that certain stationary sets evade approachability under weak square principles. These results highlight \clubsuit_\kappa's utility in bounding cardinalexponentiation and iterating forcing notions while preserving combinatorial properties.[109][110]
Commercial and brand uses
Club Med
Club Med is a French multinational resort operator specializing in all-inclusive vacation experiences, founded in 1950 by Belgian entrepreneur Gérard Blitz as a sports-focused holiday village in Alcúdia, Majorca, Spain.[111] Initially conceived as an affordable escape promoting communal activities and freedom from everyday constraints, it quickly evolved into a global pioneer of the all-inclusive model, where guests receive unlimited meals, drinks, and organized sports like sailing and yoga in exchange for a fixed fee.[112] By 2025, the company operates 68 premium and exclusive resorts across 40 countries, emphasizing upscale, activity-driven stays that blend relaxation with adventure.[113]The business model centers on self-contained "villages" that cater to diverse demographics, including family-friendly options with kids' clubs and supervised activities, alongside eco-conscious properties certified under Green Globe standards for sustainable practices such as waste reduction and local sourcing.[114] Club Med's revenue model relies on these comprehensive packages, generating a record business volume of €2.09 billion in 2024, driven by high demand for its mountain and beach destinations.[115] Notable expansions include renovations and new openings, reflecting a strategic shift toward premium offerings since the early 2010s, with all resorts now classified as Premium or Exclusive Collection to enhance luxury elements like gourmet dining and wellness programs.[116]Culturally, Club Med revolutionized mass tourism by democratizing international travel in the post-World War II era, fostering a sense of global community through multilingual staff and shared experiences that attracted over 1.5 million guests in 2024 alone.[117] However, the company faced controversies in the 2010s and early 2020s over labor practices, including reports of overwork, low pay for seasonal "G.O.s" (Gentils Organisateurs), and discriminatory wages for temporary foreign workers at resorts like Quebec Charlevoix.[118] In response, Club Med has committed to sustainability goals, such as achieving 100% renewable energy for European resorts by 2030 and eliminating single-use plastics across properties.[119]Following the COVID-19 pandemic, Club Med achieved a robust recovery, with average room occupancy reaching 75% in 2024—a two-point increase from the prior year—fueled by pent-up travel demand and expanded capacity of 4% through renovations.[120] To modernize guest engagement, the company launched the "My Club Med" mobile app, enabling digital bookings for activities, real-time schedule access, and personalized itineraries before and during stays.[121] This digital integration supports its ongoing growth, with plans for new resorts in regions like Southeast Asia and the Gulf States by 2026.[122]
Sam's Club
Sam's Club is a membership-only retail warehouse club chain owned by Walmart Inc., specializing in bulk purchases of groceries, electronics, apparel, and other consumer goods at discounted prices to small businesses and individual shoppers. Founded by Walmart founder Sam Walton, it opened its first location on April 7, 1983, in Midwest City, Oklahoma, as an experiment in the emerging warehouse club model inspired by competitors like Price Club. By 2025, Sam's Club operates over 600 locations primarily in the United States across 44 states and Puerto Rico, with additional stores in China and a few other international markets, serving approximately 50 million paid members.[123][124]The chain's operations revolve around a membership-based economic model, where annual fees generate significant revenue alongside merchandise sales; the basic Club membership costs $50 per year, while the premium Plus tier at $110 includes perks such as 2% cash back on purchases, free shipping on most online orders, and access to additional services like optical centers, pharmacies, tire and battery services, and fuel stations offering discounted gasoline. Members access bulk items in large-format stores averaging 134,000 square feet, emphasizing value through limited selection of high-turnover products from national brands and Sam's private-label Member's Mark line. This model competes directly with Costco Wholesale, though Sam's Club differentiates with integrated Walmart supply chain efficiencies and a focus on digital tools like the Scan & Go mobile app for contactless shopping. In fiscal year 2024 (ended January 31, 2024), Sam's Club reported net sales of $86.3 billion, contributing to Walmart's overall portfolio while prioritizing operational margins through membership renewals exceeding 90%.[125][126][127]Historically, Sam's Club was established as a subsidiary of Walmart during the company's expansion in the 1980s, with early growth funded by Walmart's resources and no formal merger required since it was internally developed; by 1987, it had acquired smaller chains to accelerate expansion into urban and Midwestern markets. International growth began with the opening of its first store in Shenzhen, China, on August 12, 1996, marking Walmart's push into Asian markets, followed by gradual additions reaching about 50 clubs there by 2025. Digital innovations emerged in the 2010s, including the launch of the standalone Scan & Go app in 2016 for in-club scanning and checkout, which was integrated into the main Sam's Club app in 2018 to enhance e-commerce and curb-side pickup options.[123][128][129][130]As part of Walmart's broader environmental commitments, Sam's Club participates in sustainability initiatives aimed at reducing its ecological footprint, including a corporate goal to power all global operations with 100% renewable energy by 2035 through investments in solar, wind, and community solar projects that supplied nearly 50% of Walmart's electricity needs in 2024. These efforts extend to product sourcing, with targets for Member's Mark items to incorporate sustainable materials like recycled packaging and responsibly sourced seafood by 2025, aligning with Walmart's zero-emissions ambition by 2040.[131][132][133]
Scientific and other uses
Club good
A club good in economics is characterized as excludable but non-rivalrous, allowing providers to restrict access through mechanisms like fees or memberships while one individual's consumption does not diminish availability for others, at least until reaching capacity thresholds where congestion may introduce rivalry.[134] This concept was introduced by James M. Buchanan in his 1965 paper "An Economic Theory of Clubs," which analyzed how such goods occupy an intermediate position between purely private goods (rivalrous and excludable) and public goods (non-excludable and non-rivalrous).[134] Buchanan emphasized exclusion as a tool to internalize benefits within a defined group, preventing overuse and enabling efficient private provision.[135]Club goods contrast sharply with public goods, such as clean air or lighthouses, which cannot feasibly exclude non-payers and remain non-rivalrous regardless of usage scale.[136] Representative examples include cable television, where paying subscribers access programming without reducing the service for others; private gyms, offering equipment and space that support multiple simultaneous users up to facility limits; and uncongested toll roads, which bar non-payers via barriers but permit parallel vehicle travel without resource depletion.[137] These illustrations highlight how club goods facilitate targeted consumption while mitigating the free-rider issues plaguing public alternatives.[138]The underlying theory advocates for optimal provision via voluntary "clubs"—groups of users who jointly fund and manage the good—to balance scale economies against congestion.[134] Buchanan's mathematical model frames this as utility maximization for members, where total utility rises with additional participants due to cost-sharing but eventually declines from congestion; the equilibrium club size occurs when marginal benefit from an extra member equals marginal congestion cost, typically with membership (N) below full capacity to preserve non-rivalry.[135] This approach avoids the underprovision of public goods by enabling exclusionary pricing that captures user willingness to pay.[139]Applications in urban economics often involve gated communities, where residents form clubs to finance exclusive infrastructure like private security and recreational facilities, thereby enhancing collective welfare through enforced access controls.[140] Policy implications for digital content underscore club goods' role in scalable provision; Netflix, for example, operates as such by granting unlimited video streaming to its 301.6 million global subscribers as of 2025, excluding non-members while ensuring non-rivalrous access absent bandwidth constraints.[141] Such models inform regulations balancing innovation with equitable access in information economies.[142]Post-2020 studies on the sharing economy have applied club goods analysis to platforms like Uber, viewing ride-hailing as excludable via app registration and payment but non-rivalrous in matching supply to demand up to surge limits, thus optimizing resource allocation in dynamic markets.[143]
Club (anatomy)
In anatomy, a "club" refers to various enlarged or bulbous structures in biological organisms, often serving defensive, sensory, or structural roles. One prominent example is the tail club of ankylosaurid dinosaurs, an armored group from the Late Cretaceous period. This structure consists of a stiffened "handle" formed by interlocking caudal vertebrae and a bulbous "knob" composed of fused osteoderms at the tail's end, enabling powerful swings for defense.[144] In species like Euoplocephalus tutus, the knob could reach widths of up to 620 mm and generate impact forces sufficient to fracture the bones of predators such as Tyrannosaurus rex, with estimated club masses around 20 kg based on biomechanical analyses.[145]Fossil evidence of advanced tail clubs dates to approximately 70 million years ago in North American formations, though precursor features evolved stepwise as early as the mid-Cretaceous around 110 million years ago.[144]In mammals, club-like formations appear in both skeletal and neural contexts. Some rodents, particularly African mouse-like species in the subfamily Deomyinae, possess embedded osteoderms—bony scales beneath the tail skin—that provide reinforcement similar to ankylosaur armor, potentially aiding in locomotion or protection.[146] Neural clubs manifest as specialized sensory endings, such as the club-like terminals of trigeminal neurons innervating rat vibrissae (whiskers), which detect mechanical stimuli with high firing frequencies up to 300 Hz during air puff stimulation, facilitating tactile exploration.[147] These endings, characterized by bulbous morphology and dense neurofilaments, integrate with other mechanoreceptors to encode environmental textures and vibrations.[148]A notable modern analog is the human clubfoot, or congenital talipes equinovarus (CTEV), a musculoskeletal deformity where the foot is rotated inward and downward due to abnormal tendon and ligament development. It affects approximately 1.18 per 1,000 live births globally, with higher rates in certain populations like those of Polynesian descent.[149] Treatment primarily involves the non-surgical Ponseti method of serial casting and bracing, often supplemented by minor surgical tenotomy, achieving correction in over 95% of idiopathic cases when initiated early.[150]Emerging research highlights club structures in insects, such as the clubbed antennae of butterflies (Lepidoptera: Papilionoidea), which feature enlarged distal segments packed with olfactory sensilla for detecting pheromones and host plants. A 2024 morphological study of Danaus species revealed that these clubs contain multiporous sensilla that enhance chemosensory acuity.[151] These natural clubs parallel manufactured weapons in form but evolved for sensory rather than combative purposes.