Pound
Pound most commonly refers to: Pound or pounds may also refer to:Units of measurement
Pound-mass
The pound-mass, commonly referred to as the avoirdupois pound, is a unit of mass in both the imperial and United States customary systems of measurement, defined as exactly 0.45359237 kilograms. It is subdivided into 16 avoirdupois ounces, with each ounce equaling 28.349523125 grams. This definition ensures precise equivalence to the metric system for international consistency. The historical origins of the pound trace back to the ancient Roman libra, a unit of mass approximately equivalent to 327 grams that served as a standard for trade and was divided into 12 uncia (ounces). Evolving through medieval European and English systems, the avoirdupois pound—distinct from lighter systems like troy for commodities—weighed about 454 grams by the 14th century and was refined over time through national standards. Standardization occurred in 1959 via the International Yard and Pound Agreement, signed by representatives from the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa, which aligned the pound's definition across these nations to exactly 0.45359237 kilograms, resolving minor discrepancies between prior U.S. and imperial versions.[1] In contemporary usage, the avoirdupois pound is the standard for everyday mass measurements in the United States, including body weight (e.g., expressed as pounds) and food quantities (e.g., pounds of produce), while the troy pound—equal to about 0.373 kilograms and divided into 12 troy ounces—is reserved for weighing precious metals like gold and silver. This distinction prevents confusion in specialized trades, though the avoirdupois pound dominates general commerce and consumer applications. Key conversions include the exact relation to the metric system, given by: $1 \, \mathrm{lb} = 0.45359237 \, \mathrm{kg} or, in grams: $1 \, \mathrm{lb} = 453.59237 \, \mathrm{g} One avoirdupois pound equals 7,000 grains, providing a finer subdivision for precision. Since the 1959 agreement, the avoirdupois pound in the imperial system and U.S. customary system has been identical, eliminating prior slight variations (e.g., the pre-1959 U.S. pound was marginally heavier). The pound-mass measures inertial mass, in contrast to the pound-force, which quantifies gravitational force on that mass.Pound-force
The pound-force (symbol: lbf or lb_f) is a unit of force in the foot–pound–second (FPS) system of units, defined as the gravitational force acting on one avoirdupois pound-mass (lbm) at standard gravity on Earth's surface.[2] This unit equals approximately 4.448 222 newtons (N) in the International System of Units (SI).[2] The pound-force derives from Newton's second law of motion, F = ma, where the force F is the weight of a mass m under acceleration a = g (standard gravitational acceleration). Thus, the relation is given by $1 \, \mathrm{lbf} = 1 \, \mathrm{lbm} \times g, with g \approx 32.174 \, \mathrm{ft/s^2} (equivalent to 9.806 65 m/s²).[3] This derivation ensures consistency in engineering calculations involving both mass and force within the FPS framework. The pound-force emerged in 20th-century American engineering as part of the gravitational FPS system, which treats the pound ambiguously as both a mass and force unit but incorporates the gravitational constant g_c = 32.174 \, \mathrm{lbm \cdot ft / (lbf \cdot s^2)} to reconcile Newton's laws and distinguish it from absolute systems using the poundal (pd) as the force unit.[3] This approach addressed ambiguities in earlier imperial practices, promoting clarity in dynamic analyses.[4] In practical applications, the pound-force is widely used in US aerospace and mechanical engineering for quantifying loads, such as engine thrust (e.g., a typical small jet engine producing thousands of lbf) and structural stresses.[5] It facilitates conversions to SI units via the factor 1 lbf ≈ 4.448 222 N, essential for international standards compliance in fields like aircraft design and automotive mechanics.[2]Currency
Pound sterling
The pound sterling, with the currency code GBP and symbol £, serves as the official currency of the United Kingdom, including England, Scotland, Wales, and Northern Ireland, as well as the Crown Dependencies of Jersey, Guernsey, and the Isle of Man, and certain British Overseas Territories such as the British Antarctic Territory and the British Indian Ocean Territory.[6][7] It is subdivided into 100 pence, with the singular form being penny, a structure established through decimalization in 1971 that replaced the pre-decimal system of 12 pence to a shilling and 20 shillings to a pound.[8][9] The Bank of England, as the UK's central bank, holds responsibility for issuing banknotes, while the Royal Mint produces coins, ensuring the currency's stability and security.[6] The origins of the pound sterling trace back to Anglo-Saxon England around the 8th century, when it functioned as a unit of account equivalent to one pound weight of silver, initially minted as 240 silver pennies under King Offa of Mercia.[10][11] This silver-based system evolved after the Norman Conquest in 1066, with the term "sterling" referring to high-quality silver pennies, and the first gold sovereign coin appearing in 1489 under Henry VII.[11] The pound adopted the gold standard through the Coinage Act of 1816, which fixed its value to a specific weight of gold, marking a shift from silver and establishing Britain as a leader in international monetary policy until the standard's suspension in 1931 amid economic pressures.[12][13] Decimalization on 15 February 1971 modernized the currency by introducing new pence, phasing out shillings and pence over an 18-month period to simplify transactions.[8] In its current form, the pound sterling circulates through coins in denominations of 1p, 2p, 5p, 10p, 20p, 50p, £1 (12-sided since 2017), and £2, all produced by the Royal Mint with bimetallic designs for higher values to enhance security.[14] Banknotes, issued by the Bank of England, in denominations of £5, £10, £20, and £50, transitioned to durable polymer material starting with the £5 note in September 2016, featuring advanced security elements like holograms and transparent windows; the £20 polymer note was introduced in 2020 and the £50 in 2021, completing the series.[6][15] Scottish and Northern Irish banks issue their own £5 to £100 polymer notes under Bank of England oversight, while the Crown Dependencies produce localized versions pegged to sterling.[6] As one of the world's oldest currencies in continuous use, dating to the 8th century, the pound sterling plays a pivotal role in global finance, serving as a major reserve currency and influencing international trade.[16] Its value has experienced notable fluctuations, particularly post-Brexit referendum in 2016, when the pound depreciated by about 15% against the US dollar within months due to uncertainty over EU relations; by November 2025, the sterling effective exchange rate index stood at around 104 (Bank of England trade-weighted index), reflecting ongoing pressures from inflation, trade barriers, and geopolitical events, though it has shown modest recovery amid Bank of England interest rate adjustments.[17][18][19] The currency's historical resilience underscores its economic significance, underpinning the UK's £2.8 trillion GDP in 2024 and facilitating transactions in a post-Brexit landscape of adjusted EU trade dynamics.[20]Other pound currencies
Several currencies outside the United Kingdom have adopted the name "pound," often tracing their origins to British colonial influences during the 19th and 20th centuries, when the pound sterling served as a model for monetary systems in territories under British administration.[21] For instance, the Australian pound was introduced in 1910 as Australia's official currency, directly modeled on the British system of pounds, shillings, and pence, and remained in use until decimalization on February 14, 1966, when it was replaced by the Australian dollar.[22] Similarly, the New Zealand pound circulated from the early 1930s, marking New Zealand's first national currency after relying on British and Australian coins, and was discontinued in 1967 with the shift to dollars and cents. The Irish pound, or punt, was established in 1927 as the Saorstát pound following Irish independence, maintaining parity with the British pound sterling until 1979, and persisted until Ireland adopted the euro in 1999, with physical euro notes entering circulation in 2002.[23] In the Middle East and Africa, pound currencies emerged partly through colonial ties and post-independence adaptations, with several still in use today. The Egyptian pound (EGP) was introduced in 1834 under Muhammad Ali Pasha through a decree establishing a bimetallic system based on gold and silver, replacing the piastre and initially valued equivalently to the British pound; it has since evolved into a managed float, with the exchange rate at approximately 47.23 EGP per USD as of November 10, 2025.[24][25] The Sudanese pound (SDG) originated in 1957 upon Sudan's independence, splitting from the Egyptian pound at par (1:1) and issued by the Sudan Currency Board to assert economic sovereignty; it now trades at around 600.50 SDG per USD as of November 10, 2025, amid ongoing economic challenges.[26][27] The Lebanese pound (LBP) was formalized in 1948 via a monetary agreement with France that decoupled it from the French franc post-independence, establishing it as Lebanon's independent currency pegged initially to the USD; by November 10, 2025, it has depreciated severely to about 89,509 LBP per USD due to a prolonged financial crisis since 2019.[28][29] The Syrian pound (SYP), introduced during the French mandate in 1920 as the Syrian-Lebanese pound (replacing the Ottoman lira and pegged to the French franc), became Syria's distinct currency after the 1948 split with Lebanon; in August 2025, the government announced a revaluation by removing two zeros from the currency to combat hyperinflation, with the rate at approximately 11,060 SYP per USD as of November 7, 2025.[30][31] These non-UK pound currencies often reflect local adaptations to global economic pressures, particularly in the Middle East, where high inflation has eroded purchasing power and prompted unconventional exchange mechanisms. For example, Lebanon's 2020s crisis led to a parallel market where the USD effectively dominates transactions, while Syria's civil war since 2011 caused over 99% devaluation, exacerbating reliance on informal dollarization.[32] In Egypt, inflation eased to 12.5% in October 2025 from peaks above 30% in prior years, supported by IMF-backed reforms and a flexible exchange regime, though it continues to strain households.[33] Sudan's pound has faced similar inflationary turmoil amid conflict, with rates fluctuating wildly and contributing to economic isolation.[34]Symbols
Pound sign (£)
The pound sign (£) originated as a stylized uppercase "L" derived from the Latin word libra, meaning a unit of weight equivalent to a Roman pound, which evolved into a monetary denomination in medieval Europe.[35] This abbreviation was commonly used in financial records to denote pounds of silver or currency value, with the crossbar added to distinguish it from the plain letter L.[11] One of the earliest documented uses of the stylized £ appears in a 1660 cheque held in the Bank of England's archives, predating the institution's founding and indicating its established role in English commerce by the mid-17th century.[35] Over time, the design of the £ symbol evolved in typography, featuring a single vertical stroke with one or two horizontal crossbars depending on stylistic preferences and regional conventions; the double-bar version was more common historically, while the single-bar form gained prominence in the 20th century for simplicity.[35] In modern digital standards, it is encoded as Unicode U+00A3 in the Latin-1 Supplement block, introduced in Unicode version 1.1 in 1993 to support international text processing. Font variations may include subtle ligatures or flourishes, such as those emphasizing its association with sterling in British contexts, though the core glyph remains consistent across typefaces.[36] The £ symbol serves as the standard notation for the pound sterling (GBP), the United Kingdom's currency, as well as other historical and contemporary pound-based currencies like the Egyptian pound (EGP) and Syrian pound (SYP).[37] It is conventionally placed before the numerical amount, as in £10, to indicate value in financial documents, receipts, and pricing.[37] Historically, the symbol appeared on Bank of England banknotes starting from the institution's early handwritten issues in 1694, where the £ and initial digit were pre-printed for efficiency, marking its integration into official monetary representation by the late 17th century.[38] Its international recognition stems from widespread adoption in global trade and finance, aligned with ISO 4217 currency codes that reference pound-denominated units, ensuring compatibility in cross-border transactions.[39] In contemporary usage, the £ symbol is accessible via standard digital input methods, such as pressing Shift+3 on UK keyboard layouts, facilitating its entry in software and online forms.[37] This placement reflects its primary association with the pound sterling, promoting ease of use in both print and electronic media while maintaining accessibility for screen readers and international users through Unicode compliance.Number sign (#)
The number sign, denoted as #, is commonly attributed to the Latin phrase libra pondo, meaning "pound by weight," evolving from the ligature of "l" and "b" in "lb" into its current crossed-line form by the 19th century, with documented uses dating back to at least the 17th century.[40] This symbol, also known as the octothorpe—a term coined in the 1960s by Bell Labs engineers to describe its eight-pointed shape—has a loose historical tie to the abbreviation for pound-mass in measurement contexts.[41] In North America, particularly in telephony, the # is commonly referred to as the "pound sign" due to its longstanding association with denoting weight in numerical contexts, such as "5#" for five pounds; this naming became standardized on touch-tone keypads introduced by Bell Telephone in the 1960s to facilitate automated data entry.[42] Outside North America, it is more frequently called the "hash" or "hash mark," reflecting British English conventions for the symbol's grid-like appearance.[41] The number sign serves multiple purposes across domains. In general writing and numbering, it precedes figures to indicate sequence or position, as in "#1" for "number one." In social media, it gained prominence as the hashtag, popularized by Chris Messina's 2007 proposal on Twitter to group related posts (e.g., #example), transforming it into a tool for content discovery and viral trends.[43] In programming, # denotes single-line comments in languages like Python, Perl, and Ruby, allowing developers to add explanatory notes ignored by the compiler (e.g.,# This is a comment), and serves as a preprocessor directive in C and C++ for conditional compilation.[44]
Typographically, the number sign is encoded as Unicode U+0023 in the Basic Latin block, ensuring consistent rendering across digital platforms.[45] It is distinct from the musical sharp symbol (♯, Unicode U+266F), which features altered lines for notational precision, though # is sometimes used informally in text-based music discussions. By 2025, the # continues to play a pivotal role in digital culture, underpinning hashtags on platforms like Instagram and TikTok for algorithmic categorization, enhancing user engagement in global conversations, and facilitating data entry in apps for quick tagging and search optimization.[43]