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Union

A labor union, also known as a , is an organization of workers who collectively with employers to improve wages, benefits, working conditions, and job security. These associations emerged prominently in the amid industrialization, with early U.S. examples like the founded in 1866 advocating for shorter workdays and broader worker protections. Key legislative milestones, such as the National Labor Relations Act of 1935, formalized rights, enabling unions to represent workers without employer interference. Unions have achieved notable gains in elevating standards for members, including higher —often 10-20% premiums over non-union counterparts—and enhanced protocols that reduced hazards. They have also influenced broader economic norms, compressing inequality in certain sectors by pressuring non-union employers through "threat effects" and contributing to policies like the eight-hour workday. However, empirical analyses reveal trade-offs: while boosts in some firm-level studies via better worker retention and , it frequently restricts labor market flexibility, leading to reduced opportunities, particularly for and older workers, and potential suppression for non-members in competitive industries. Controversies persist around unions' monopolistic tendencies, which can lock workers into lower-mobility roles and exacerbate during economic downturns, as evidenced by cross-national data linking higher union density to slower job creation. Historical tensions include exclusionary practices toward minority workers and involvement in jurisdictional disputes or secondary boycotts, prompting reforms like the Taft-Hartley Act of 1947 to curb excesses such as closed shops. Despite declining membership in recent decades—from over 30% of U.S. workers in the to around 10% today—unions remain influential in public sectors and continue to shape debates on labor market dynamics through causal mechanisms like versus market distortions.

Abstract concepts

Mathematics and logic

In , the union of two sets A and B, denoted A \cup B, is the set containing all elements that belong to A, or to B, or to both, formally defined as \{ x \mid x \in A \lor x \in B \}. This operation is associative and commutative, meaning (A \cup B) \cup C = A \cup (B \cup C) and A \cup B = B \cup A, with the serving as the since A \cup \emptyset = A. Unions extend to arbitrary families of sets; for an indexed family \{A_i\}_{i \in I}, the union is \bigcup_{i \in I} A_i = \{ x \mid \exists i \in I \text{ such that } x \in A_i \}, which includes countable unions like \bigcup_{n=1}^\infty A_n used in for limits of increasing sequences. The union operation satisfies in relation to intersection and complement: \overline{A \cup B} = \overline{A} \cap \overline{B}, where the bar denotes set complement relative to a , enabling proofs of set identities via . In measure theory, the union of measurable sets is measurable, and for disjoint sets, the measure is additive: if A_i are pairwise disjoint, then \mu(\bigcup A_i) = \sum \mu(A_i), a foundational property for Lebesgue integration established by Henri Lebesgue in 1902. This extends to probability theory, where the union rule for events P(A \cup B) = P(A) + P(B) - P(A \cap B) quantifies the probability of at least one event occurring, derived from Kolmogorov's axioms formalized in 1933./03%3A_Measure_Theory/3.03%3A_Outer_Measure_Completeness_Cantor_Sets) In logic, union corresponds to the inclusive disjunction (\lor) when interpreting sets via s, where the of A \cup B is \chi_{A \cup B}(x) = \chi_A(x) \lor \chi_B(x), linking to propositional logic under the correspondence that holds in Boolean algebras. This connection underpins cylindric algebras and relation algebras in , where unions model disjunctive combinations of relations, as developed by in the 1940s for representations. In predicate logic, unions appear in quantifier-free formulas equivalent to disjunctions over atomic predicates, facilitating via , though disjunction's non-associativity in contrasts with classical settings.

Etymology and general definitions

The English word union derives from the Latin noun uniō (stem union-), meaning "oneness," "unity," or "a single large pearl," which is formed from ūnus, the numeral "one." This Late Latin term entered Old French as union, denoting the "action of joining," an "agreement," or the "state of matrimony," before being borrowed into Middle English around the early 15th century (circa 1415–1425) with comparable senses, initially emphasizing unification or concord. Broadly defined, a union constitutes the act, instance, or result of combining two or more distinct elements, entities, or into a cohesive whole, implying a transition from plurality to while preserving underlying components. This core notion of or oneness applies across domains, from the mathematical merging of sets to the marital or contractual bonding of , and extends to associative bodies formed for mutual purpose, such as alliances of or groups. Dictionaries consistently frame it as "the state of being united" or "something formed by uniting," underscoring or joint without subsuming identities entirely.

Science and technology

Physical and biological sciences

In physics, unification refers to the integration of disparate fundamental forces or phenomena into a single coherent theoretical framework, driven by the principle that nature's laws should exhibit underlying symmetry and simplicity. The earliest significant unification occurred with Isaac Newton's (1687), which united terrestrial and under the universal law of gravitation, demonstrating that the same force governs falling apples and planetary orbits. This was followed by James Clerk Maxwell's 1865 formulation of electromagnetic theory, which merged , , and into a unified field described by four partial differential equations, predicting electromagnetic waves propagating at the . Twentieth-century progress included the electroweak unification, proposed in 1967–1968 by Sheldon Glashow, Abdus Salam, and Steven Weinberg, which combined the electromagnetic and weak nuclear forces via the SU(2) × U(1) gauge symmetry, spontaneously broken by the Higgs mechanism. Experimental validation came in 1983 with the discovery of the W± and Z0 bosons at CERN's Super Proton Synchrotron, confirming the theory's predictions to within experimental precision and earning the 1979 Nobel Prize in Physics for Glashow, Salam, and Weinberg. Grand unified theories (GUTs), such as the SU(5) model proposed by Georgi and Glashow in 1974, extend this by merging the strong nuclear force with electroweak interactions at energies around 10^15 GeV, implying phenomena like proton decay (lifetime >10^34 years, unobserved in experiments like Super-Kamiokande as of 2025) and magnetic monopoles, though no direct evidence has emerged. Efforts to unify with persist, as and remain incompatible at Planck scales (∼10^19 GeV), with candidates like and proposing extra dimensions or quantized but lacking empirical confirmation. In , union primarily denotes the fusion of haploid s during fertilization, the process initiating and restoring diploidy in the . Fertilization is defined as the union of two s— and —leading to syngamy, where their nuclei merge to form a genetically unique diploid capable of embryonic development. This event, conserved across eukaryotes, involves sperm-egg recognition via surface proteins (e.g., Izumo1 on sperm binding on egg in mammals), acrosomal , and mediated by fusogenic proteins like EFF-1 and AFF-1 orthologs, preventing through cortical granule and . In humans, fertilization typically occurs in the ampulla of the within 12–24 hours post-ovulation, with success rates varying by factors such as viability and molecular compatibility, contributing to via meiotic recombination. Disruptions in gamete union underlie , affecting ∼15% of couples, and are studied in model organisms like and sea urchins for conserved mechanisms.

Computing and engineering

In , a union is a user-defined that enables of variables of different types in the same location, with all members overlapping at offset zero, allowing only one member to hold a value at a time. This contrasts with structures, where members occupy sequential memory; unions conserve space for scenarios like variant records but require awareness of the active member to avoid . Languages such as , , and variants in support unions, often implemented for low-level or tagged unions with discriminants to track the current type. In database query languages like SQL, the UNION operator merges result sets from two or more SELECT statements into a single set, automatically eliminating duplicate rows and requiring compatible column counts, data types, and orders. extends this by retaining duplicates, which can improve performance in large datasets by skipping deduplication. These operators facilitate combining data from disparate tables or sources, such as aggregating sales from regional queries, but demand sorted inputs for optimal execution in systems like . The union-find data structure, also known as disjoint-set union (DSU), manages a partition of a finite set into disjoint subsets through two primary operations: find, which determines the representative (root) of an element's subset, and union, which merges two subsets. With optimizations like path compression in find (flattening tree paths) and union by rank or size (attaching smaller trees to larger roots), it achieves amortized nearly constant time per operation, O(α(n)) where α is the inverse Ackermann function, growing slower than any primitive recursive function. Applications include detecting cycles in Kruskal's minimum spanning tree algorithm (by rejecting unions of already connected components) and connectivity queries in graphs with up to millions of nodes. In and , a union is a specialized fitting that joins two pipe ends via threaded or soldered connections with a central , enabling disassembly of one pipe section without rotating the entire , which simplifies maintenance or repairs in fixed installations. Typically constructed from materials like , malleable iron, or to match system pressures (e.g., up to 150 for standard threaded unions), it features ends with a secured by the , distinguishing it from couplings that require full pipe rotation for separation. Unions are standardized under codes like ASME B1.20.1 for NPT threads and used in water, gas, or lines, though they introduce minor leak risks if not properly torqued, necessitating periodic inspections.

Social, economic, and political organizations

Labor and trade unions

Labor unions, also known as , are organizations formed by workers to collectively negotiate with employers over wages, hours, benefits, and working conditions, typically through agreements. These entities aim to counterbalance employer power in the labor market, often engaging in strikes or other actions to enforce demands. The terms "labor union" and "trade union" are largely synonymous, though "trade union" historically emphasized craft-based groups while "labor union" encompasses broader industrial organizations. The modern labor union emerged during the in 18th-century , where factory systems displaced guild-like artisan associations and exposed workers to exploitative conditions, prompting organized responses. In the United States, early unions formed in the 1790s among skilled trades like printers and carpenters, but widespread organizing accelerated in the 1830s amid economic downturns and poor factory conditions. The , established on August 20, 1866, marked the first national U.S. effort to unite workers across trades, advocating for an eight-hour workday. Growth intensified post-Civil War with immigration and industrialization, leading to federations like the in 1886, which focused on craft unions rather than radical political reform. Unions operate through democratic structures, electing leaders to represent members in negotiations, grievance handling, and political advocacy. Core activities include to secure contracts, which covered 25.4% of U.S. workers in 2023 per data, often yielding higher wages—about 10-20% premiums for union members based on empirical analyses. Strikes serve as , as seen in the 1981 Professional Air Traffic Controllers Organization walkout, where 11,345 workers were fired after defying a federal , demonstrating unions' capacity for disruption but also vulnerability to employer countermeasures. Unions also lobby for legislation, influencing laws like the National Labor Relations Act of 1935, which legalized in the . Economically, unions raise compensation for represented workers but correlate with reduced and firm . A 2025 Mercatus Center study of U.S. data found that stronger union power boosts short-term wages yet increases by displacing non-union labor and deterring hiring. Similarly, Fraser Institute analysis of firm-level data shows unionized establishments experience 10-15% lower productivity growth and expansion due to rigid contracts limiting flexibility. Cross-country evidence from indicates firm-level union density raises wages by 3-5% but has negligible or negative productivity effects, challenging claims of broad efficiency gains. These outcomes reflect causal mechanisms where wage bargaining elevates costs, prompting or , as evidenced by manufacturing's union-driven decline in the U.S. from 30% density in 1950s to under 10% today. Membership has declined globally amid and right-to-work laws. In 2024, U.S. union density stood at 9.9%, down from 33.5% in 1945, with only 14.5 million members amid a 167 million workforce. data for 2023/24 reports average density at 15%, halved since 1985, with highs in like (90.6%) and lows in (8%).
Country/RegionUnion Density (%)YearSource
Iceland90.62024OECD
United States9.92024BLS
OECD Average152023/24OECD
Criticisms include corruption, as in historical cases like the under , convicted in 1964 for and , highlighting risks of unchecked leadership power. Strikes impose externalities, such as the 2023 action costing $8.3 billion in lost output per estimates, without proportional gains for non-participants. Empirical reviews note unions' political alignment often favors expansive government, potentially entrenching inefficiencies, though pro-union sources like the emphasize productivity spillovers unverified in neutral studies. These dynamics underscore unions' role in redistributing rather than expanding the economic pie, with benefits concentrated on insiders at broader societal cost.

Political and historical unions

A entails the integration of two or more previously independent polities into a shared , typically involving the pooling or transfer of over matters such as , , or , while retaining distinct identities to varying degrees. Unlike loose confederations, where member states maintain full and the central depends on voluntary compliance, political unions establish binding institutions that exercise compulsory over participants. Forms include unions, where states share a single but operate separate administrations; real unions, which combine shared institutions like a common or without full merger; and incorporating unions, resulting in a unitary entity. Early historical examples often stemmed from dynastic or . The , formed in 1397 under Queen , united the kingdoms of , and under a single monarch, with ambitions for centralized rule that included joint councils but ultimately dissolved amid internal revolts by 1523 due to resistance against Danish dominance. Similarly, the between the crowns of and from 1580 to 1640 arose when inherited the Portuguese throne, leading to coordinated foreign policy but preserving Portugal's laws and autonomy until a rebellion restored independence. In the , voluntary parliamentary unions emerged in . The merged the Kingdom of and the Kingdom of Scotland into the Kingdom of , uniting their parliaments in on May 1, , while compensating Scottish elites with economic access to English colonies; this incorporating union addressed fiscal imbalances and security threats but sowed seeds of later nationalist discontent. The 1800 Act of Union incorporated into , effective January 1, 1801, centralizing representation amid post-rebellion coercion, though was delayed until 1829, exacerbating tensions that contributed to partition in 1921. Nineteenth-century unifications often involved federal or models amid . The , proclaimed January 18, 1871, under Prussian leadership, federated 26 states into a with a shared and military command, standardizing weights, measures, and tariffs while preserving monarchical autonomies. The created a between and , with common ministries for finance, defense, and but separate parliaments, stabilizing the Habsburg realm after defeat in the until dissolution in 1918 amid ethnic strife. Twentieth-century examples include both consensual federations and coerced mergers. The , established January 1, 1901, via the Commonwealth Constitution, united six colonies into a federal dominion with a central in , balancing state powers with national authority over trade and defense. Conversely, the of March 12, 1938, forcibly annexed Austria into as a unitary province, violating the 1919 Treaty of Saint-Germain and justified by pan-German ideology, only to be reversed post-World War II. The , a short-lived union between and from February 1958 to September 1961, featured a shared presidency under but collapsed due to Syrian elite resistance to Cairo's centralization. In the contemporary era, the represents an evolving supranational political union. Founded via the on November 1, 1993, it encompasses 27 member states sharing institutions like the , , and Court of Justice, with competences in (for members), , and justice, though and taxation remain intergovernmental; this framework has fostered economic convergence but sparked debates over sovereignty erosion, as evidenced by the United Kingdom's withdrawal effective January 31, 2020. Political unions frequently endure through economic interdependence and shared threats but risk dissolution from cultural divergences or power asymmetries, as causal analysis of historical failures reveals imbalances in representation and resource allocation as key precipitants.

Educational and civic unions

Educational unions primarily consist of professional associations and labor organizations representing s, school staff, and higher education faculty. These groups focus on for compensation and conditions, , and influencing to enhance teaching quality and student outcomes. The (NEA), established in 1857, serves as the largest such entity in the United States, with about 2.5 million active members in 2024, including educators from preschool through higher education levels. The (AFT), formed in 1916 as an affiliate of the , represents over 1.7 million members nationwide, emphasizing democratic processes, economic equity, and advancements in education delivery. Both organizations have historically advocated for standards, , and opposition to policies perceived as undermining schooling, though critics argue their influence sometimes prioritizes member interests over empirical measures of instructional efficacy. Civic unions, often encompassing public sector employee organizations, unite workers in municipal, county, state, and federal roles to secure fair labor practices and sustain essential community services. The American Federation of State, County, and Municipal Employees (AFSCME), chartered in 1936, exemplifies this category with more than 1.4 million members across diverse occupations such as emergency responders, highway maintenance crews, and administrative personnel. These unions negotiate contracts addressing wages, benefits, and safety protocols, while for funding to maintain like water systems and public transit; for instance, AFSCME members have been instrumental in strikes and campaigns yielding measurable gains in security and during crises like the . Unlike private-sector counterparts, civic unions operate within taxpayer-funded frameworks, raising debates on , as their derives from government employers unable to relocate or exit markets, potentially incentivizing expanded bureaucracies over efficiency.

Places

In Canada

Unionville is a heritage neighbourhood in the City of , featuring a preserved lined with 19th-century buildings that host shops, restaurants, and cultural venues. The area underwent infrastructure upgrades in the 2020s, including new sidewalks, road surfaces, and street lighting, to maintain its historic character while improving functionality. Port Union, located on the in , was established in 1916 by Sir William Coaker as the headquarters for the Fishermen's Protective Union (FPU), serving as a model "union-built" town designed to advance fishermen's interests through cooperative commerce and advocacy. The community, overlooking Trinity Bay and Catalina Harbour, embodies early 20th-century labour organization efforts, with preserved structures highlighting the FPU's role in social reform and economic self-reliance for outport fishers. Union Bay is an unincorporated seaside community on the east coast of , , situated in the Comox Valley approximately 15 kilometres south of Courtenay and 93 kilometres north of . It originated as a major coal shipping port operated by the Union Coal Company from 1888 to 1960, with remnants of its industrial wharf infrastructure still visible along Baynes Sound. Smaller locales include Union, a rural hamlet in Elgin County, Ontario, located 1 kilometre west of St. Thomas along Highway 4, with a recorded population of 345 as of recent local surveys. Union Valley, in Nova Scotia, consists of dispersed rural settlements near coordinates 45°22′39″N 64°25′2″W, lacking significant urban development.

In the United States

Numerous municipalities, townships, and counties in the United States are named "Union," often to denote the merging of communities or allegiance to national unity, with over 37 such place names recorded. Seventeen counties bear the name Union County, distributed across states including Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Mississippi, New Jersey, North Carolina, Ohio, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, and New Mexico. These names frequently originated in the 19th century, coinciding with periods of territorial organization and post-Civil War emphasis on preserving the federal union. Among larger incorporated places, , in Alameda County, had a population of 70,145 according to the ; the city was incorporated on July 1, 1976, through the consolidation of the former communities of Alvarado and Decoto. Similarly, , in Hudson County, recorded 68,589 residents in the 2020 census and developed as a dense urban area near the , historically serving as a hub for and . Union Township in , encompasses 59,728 residents as of the 2020 census and functions as a suburban adjacent to , with early settlement tied to colonial-era land grants. Smaller but notable examples include Union, Illinois, a village in McHenry County with 551 inhabitants in 2020, known for its rural character and proximity to . These locations exemplify how the term "Union" was applied to both newly formed entities and sites symbolizing cohesion amid 19th-century expansion and conflict.

Elsewhere

The Union Islands, a historical designation for the three atolls now comprising —a non-self-governing territory of in the South Pacific Ocean—were named by European explorers in the to reflect their grouped formation. These atolls, , , and , span a total land area of about 10 square kilometers and were settled by Polynesian voyagers around , with evidence of continuous habitation through oral traditions and archaeological finds of adzes and fishhooks. The islands became a in 1877 under the Western Pacific Order in Council, were annexed to in 1926 following a 1916 transfer from , and officially renamed Islands in 1946 to honor the Samoan term meaning "north atolls." As of 2023, 's population numbered approximately 1,859 residents, primarily Polynesian, with a based on , , and remittances; the territory maintains free association with while pursuing discussions. Smaller settlements named Union exist in various countries, such as municipalities in the Philippines (including Union in La Union province, with a 2020 population of around 22,000 focused on agriculture and fishing), Guatemala, Colombia, and Ecuador, often arising from Spanish colonial influences denoting communal or federated origins. In South Africa, Union in the Free State province refers to rural localities tied to early 20th-century agricultural communities, though lacking significant urban development. These locales typically feature modest populations under 5,000 and derive their names from themes of unity or merger, reflecting local historical consolidations rather than large-scale geopolitical entities.

Arts and entertainment

Music

Musicians' unions are trade organizations dedicated to safeguarding the economic and professional interests of performing artists, including of wages, working conditions, health benefits, and royalties for recordings and performances. Emerging in the late alongside the commercialization of live music halls, theaters, and early recording technologies, these unions addressed exploitation by venue owners and broadcasters who profited from musicians' labor without fair compensation. By organizing , they established scales for fees, limited work hours, and secured pensions, often through strikes against mechanized alternatives like player pianos and jukeboxes that displaced live ensembles. The (AFM), the largest musicians' union globally, was founded on October 20, 1896, in , , by delegates from 21 local unions breaking from the of Musicians. Starting with approximately 3,000 members, it expanded rapidly to 45,000 by 1906 and became international in 1897 with Canadian locals joining. Under leaders like James C. Petrillo, the AFM orchestrated pivotal actions, including the 1942–1944 recording ban, where over 100,000 members halted commercial sessions to demand royalties for broadcast reuse of records, ultimately establishing the Music Performance Trust Fund to subsidize free public concerts and counter job losses from canned music. Subsequent 1947 strikes further entrenched royalty systems, though the union faced setbacks from antitrust rulings and industry shifts toward non-union recording in the mid-20th century. Today, the AFM maintains over 140 locals, negotiating agreements across symphonies, film scores, and touring acts while advocating against digital streaming inequities. In , the United Kingdom's Musicians' Union (), formed in in as the Amalgamated Musicians' Union, pioneered protections for orchestral and variety performers amid cinema and broadcasting booms. It grew through mergers and campaigns against foreign competition and technological displacement, such as talkies reducing pit orchestras, and now represents over 36,000 members in diverse genres from classical to . Globally, the International Federation of Musicians (FIM), established in 1948, unites over 70 national affiliates to tackle cross-border issues like instrument transport regulations, AI-generated performances, and equitable streaming revenues, fostering social dialogue with bodies such as the . These entities persist in countering precarity from platform economies, where algorithmic devaluation of human artistry echoes historical battles against .

Film, literature, and other media

"The Union" is a 2024 American spy directed by , starring as a construction worker recruited by his high school sweetheart () for a covert mission, alongside and . The screenplay was written by and , with occurring in 2022; it premiered on on August 16, 2024, receiving mixed reviews for its action sequences but criticism for predictable plotting. "Union" is a 2024 directed by Brett Story and Stephen Maing, focusing on the grassroots campaign by warehouse workers at an Amazon facility in , , to establish the (ALU) amid health and safety concerns during the . Filmed in style, it highlights ALU founder and the 2022 election victory representing over 8,000 workers, though subsequent challenges including ALU dissolution in 2024 are noted. The film premiered at the on September 27, 2024, and earned praise for its portrayal of labor organizing obstacles against corporate opposition. In literature, "Union" (2022) is a novel by Canadian Sara Cassidy, centered on teenager Tuck, who confronts and budding romance while investigating union formation at his fast-food job amid exploitative conditions. Published by Book Publishers, it explores themes of and personal healing, targeting readers aged 12–15. Other media includes the television series "Union" (2013–), a documentary-style program following student life and elections at the University of York , with episodes blending real-time footage of and . Additionally, the crime web series "The Union Series" (2016) depicts rival families vying for control in , produced independently with a focus on urban underworld dynamics.

Sports

Players' associations and leagues

Players' associations in operate as labor unions, collectively bargaining with league owners and on behalf of athletes for compensation, benefits, working conditions, and such as agency and procedures. These organizations emerged in response to early inequities, including low wages, short career spans, and owner control over player mobility, transforming by tying player pay to league revenues through agreements (CBAs). The (NFLPA), founded on December 10, 1956, by players from the and , represents over 2,000 current and former players, negotiating CBAs that have established minimum salaries, pension plans, and models reaching 48% of league income by 2020. Initially unrecognized by the until 1968, the NFLPA weathered strikes in and , securing key victories like the introduction of free agency in 1993. In , the MLB Players Association (MLBPA), certified in 1968 after earlier failed attempts dating to 1912, covers approximately 5,500 minor and major league players, enforcing rules against collusion and negotiating systems to balance competitive equity with earnings that averaged $4.5 million per player in 2023. The (NBPA), established in 1954 and fully unionized by 1962, advocates for NBA players on issues like load management and media rights, with its latest in 2023 extending to 2029 and including a 10% raise in the salary cap. Internationally, the (FIFPro), formed in 1965 and headquartered in the , coordinates 70 national players' associations representing over 65,000 professional soccer players worldwide, focusing on workload regulations, transfer system reforms, and disputes with governing bodies like . FIFPro has challenged 's expanded Club World Cup format in 2025, citing player welfare concerns amid accusations of governance overreach. Other notable associations include the (NHLPA), which endured a 2012-2013 lockout to ratify a emphasizing revenue sharing at 50%, and emerging groups like the Women's National Basketball Association Players Association (WNBPA). In 2022, the launched a Sports Council to support athlete unionization across disciplines, including referees and stadium workers, reflecting broader labor solidarity. These entities maintain league stability through enforced contracts while enabling player mobility, though tensions persist over issues like antitrust exemptions and college athlete organizing.

Teams and venues

The , a Major League Soccer club founded in 2008 and based in , plays home matches at , a opened in 2010 with a capacity of 18,500 seats located along the . The venue features state-of-the-art facilities including 15 luxury suites and supports non-soccer events, with the club clinching the 2025 there.
  1. FC Union Berlin, established in 1906 and competing in the German Bundesliga, hosts games at , a historic venue in Berlin-Köpenick opened in 1920 with a current capacity of 22,012 following renovations. The stadium, situated near the Wuhle River, underwent expansions in the 2000s to meet modern standards while preserving its traditional standing terraces.
Royale Union Saint-Gilloise, a team with roots dating to 1897, utilizes Stade Joseph Mariën in , inaugurated in 1919 and holding 9,512 spectators after upgrades. The ground, on the edge of Parc Duden, has hosted matches since the 1920s but faces compliance issues prompting temporary relocations for European fixtures. , a side launched in 2019, currently plays at in —a multi-purpose facility built in 2011 with 6,434 seats for soccer—while plans for a dedicated downtown Omaha stadium remain unresolved as of January 2025.
TeamLeagueHome VenueCapacityYear Opened
Philadelphia UnionMLS (USA)18,5002010
(Germany)22,0121920
Pro League ()Stade Joseph Mariën9,5121919
(USA)6,4342011

Other uses

Military and religious

In , "union" prominently denotes the federal government and its loyal states during the (1861–1865), encompassing the collective civilian leadership under President and the that mobilized approximately 2.1 million soldiers to suppress the secession. This usage emphasized preservation of national unity against the breakaway Southern states forming the , with Union forces achieving victory through strategies of attrition, blockade, and conquest, culminating in Confederate surrender at Appomattox Court House on April 9, 1865. In , a field intersecting military symbolism, the "union" specifically refers to the rectangular section of a —typically the upper hoist-side quarter—bearing emblems of combined entities, as seen in the , which merges the crosses of St. George, St. Andrew, and St. Patrick to represent the political amalgamation of , , and under the since 1606. Similarly, the blue canton of the U.S. , containing the stars, is termed the union, symbolizing federal cohesion amid stripes representing the original colonies. In religious contexts, "union" carries profound theological weight, most notably in the , a core Christian doctrine formalized at the in 451 CE, which affirms that Jesus Christ exists as one divine person (hypostasis) subsisting in two distinct natures—fully divine and fully human—united without mixture, change, division, or separation. This formulation resolved early Christological debates, countering heresies like (which separated the natures into two persons) and (which merged them into one nature), and remains foundational to orthodox Trinitarian faith across Catholic, Eastern Orthodox, and Protestant traditions. Beyond Christology, "union" describes mystical or soteriological states, such as the believer's spiritual incorporation into Christ (), wherein divine life is imparted through faith, sacraments, and grace, as articulated in Reformed theology by figures like , who viewed it as the source of justification, sanctification, and perseverance. Ecclesiastically, unions refer to mergers of religious communities or denominations, exemplified by the 1244 unification of hermit groups into the under Pope Innocent IV's bull Incumbert nobis, establishing a order emphasizing communal poverty and Augustinian rule. Such unions aimed to consolidate fragmented monastic traditions for greater apostolic efficacy, influencing later consolidations like the International Union of Superiors General for women's religious orders. In legal contexts, a refers to a state-recognized partnership between two individuals that confers many rights and obligations akin to , such as , medical decision-making, and property division, but historically lacked full federal recognition. Introduced in on July 1, 2000, civil unions were initially designed to extend marital benefits to same-sex couples amid debates over definitions, with eight U.S. states adopting them by 2013 before the 2015 decision in extended nationwide, rendering civil unions obsolete or convertible in most jurisdictions. As of 2023, states like , , and maintain civil union statutes, treating them equivalently to marriages for state purposes, though federal benefits like Social Security survivor payments require conversion to for full portability. Civil unions differ from , which arises from and mutual intent without formal registration, whereas civil unions necessitate a state filing and ceremony. They provide targeted protections, including hospital visitation and adoption rights, but portability across states remains limited, prompting legal challenges and conversions; for instance, New Jersey's 2007 civil unions faced lawsuits over out-of-state recognition before shifting to in 2013. In financial contexts, a credit union is a member-owned, not-for-profit cooperative financial institution that offers services like savings accounts, loans, and checking, with profits returned to members via lower fees and higher yields rather than shareholder dividends. Originating from 19th-century German self-help groups pioneered by Hermann Schulze-Delitzsch in 1852 and Friedrich Raiffeisen in 1864, credit unions emphasize mutual aid for underserved borrowers, spreading to North America with the first U.S. charter in Massachusetts in 1909 under Alphonse Desjardins. By 2023, U.S. credit unions held over $2.2 trillion in assets, serving 130 million members through 4,500 institutions regulated by the National Credit Union Administration (NCUA) for federally insured ones, distinguishing them from profit-driven banks by democratic governance—one member, one vote. Credit unions' tax-exempt status under IRS Section 501(c)(14) supports their community focus, enabling competitive rates; for example, average credit union auto loan rates were 4.6% in versus 6.5% at banks, though they face for smaller scale limiting services like wires. Globally, the World Council of Credit Unions reports over 89,000 credit unions serving 390 million members as of 2024, with strong presence in and adapting the model to local regulations.