F is the sixth letter of the Latin alphabet. F may also refer to:

Science and technology

Mathematics

* F or f, the number 15 in hexadecimal and higher positional systems * _''p''''F''_''q'', the

hypergeometric function In mathematics, the Gaussian or ordinary hypergeometric function 2''F''1(''a'',''b'';''c'';''z'') is a special function represented by the hypergeometric series, that includes many other special functions as specific or limiting cases. It is ...

F-distribution In probability theory and statistics, the ''F''-distribution or ''F''-ratio, also known as Snedecor's ''F'' distribution or the Fisher–Snedecor distribution (after Ronald Fisher and George W. Snedecor), is a continuous probability distribut ...

, a continuous probability distribution **

F-test An F-test is a statistical test that compares variances. It is used to determine if the variances of two samples, or if the ratios of variances among multiple samples, are significantly different. The test calculates a Test statistic, statistic, ...

, a statistical test * f, SI prefix

femto A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple (mathematics), multiple or submultiple of the unit. All metric prefixes used today are decimal, decadic. Each prefix has a unique symbol that is prepen ...

, factor 10⁻¹⁵ * ,

Fibonacci number In mathematics, the Fibonacci sequence is a Integer sequence, sequence in which each element is the sum of the two elements that precede it. Numbers that are part of the Fibonacci sequence are known as Fibonacci numbers, commonly denoted . Many w ...

Computing and engineering

* F (programming language), a subset of Fortran 95 *

F Sharp (programming language) F# (pronounced F sharp) is a general-purpose, high-level, strongly typed, multi-paradigm programming language that encompasses functional, imperative, and object-oriented programming methods. It is most often used as a cross-platform Common ...

, a functional and object-oriented language for the .NET platform. *

F* (programming language) F* (pronounced ''F star'') is a high-level, multi-paradigm, functional and object-oriented programming language inspired by the languages ML, Caml, and OCaml, and intended for program verification. It is a joint project of Microsoft Resear ...

, a dependently typed functional language for the .NET platform. * F-measure, the harmonic mean of precision and recall * f, in programming languages often used to represent the

floating point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a signed sequence of a fixed number of digits in some base) multiplied by an integer power of that base. Numbers of this form ...

F connector F, or f, is the sixth letter of the Latin alphabet and many modern alphabets influenced by it, including the modern English alphabet and the alphabets of all other modern western European languages. Its name in English is ''ef'' (pronounc ...

, used for inlet in cable modems * F crimp, a type of solderless electrical connection * F band (NATO), a radio frequency band from 3 to 4 GHz * F band (waveguide), a millimetre wave band from 90 to 140 GHz

Physics

* °F, degree on the

Fahrenheit The Fahrenheit scale () is a scale of temperature, temperature scale based on one proposed in 1724 by the German-Polish physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accou ...

temperature scale * F, for

farad The farad (symbol: F) is the unit of electrical capacitance, the ability of a body to store an electrical charge, in the International System of Units, International System of Units (SI), equivalent to 1 coulomb per volt (C/V). It is named afte ...

, a unit for electric capacitance * or ℱ, the

Faraday constant In physical chemistry, the Faraday constant (symbol , sometimes stylized as ℱ) is a physical constant defined as the quotient of the total electric charge () by the amount () of elementary charge carriers in any given sample of matter: it ...

* ,

focal length The focal length of an Optics, optical system is a measure of how strongly the system converges or diverges light; it is the Multiplicative inverse, inverse of the system's optical power. A positive focal length indicates that a system Converge ...

of a lens **

f-number An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system's focal length by the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical ...

(sometimes called f-ratio, f-stop, or written f/), the focal length divided by the aperture diameter *

\vec F

, , ,

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

* ,

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

* F (or A),

Helmholtz Free Energy In thermodynamics, the Helmholtz free energy (or Helmholtz energy) is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature ( isothermal). The change in the Helmholtz ene ...

* ''F'', the

electromagnetic field tensor In electromagnetism, the electromagnetic tensor or electromagnetic field tensor (sometimes called the field strength tensor, Faraday tensor or Maxwell bivector) is a mathematical object that describes the electromagnetic field in spacetime. T ...

in electromagnetism *: Often generalized to include the field tensors of other interactions, as in i.e. the

gluon field strength tensor In theoretical particle physics, the gluon field strength tensor is a second order tensor field characterizing the gluon interaction between quarks. The strong interaction is one of the fundamental interactions of nature, and the quantum fiel ...

. *

F region The F region of the ionosphere is home to the F layer of ionization, also called the Appleton–Barnett layer, after the English physicist Edward Appleton and New Zealand physicist and meteorologist Miles Barnett. As with other ionospheric secto ...

, part of the ionosphere

Chemistry

Fluorine Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...

, symbol F, a chemical element *

f-block A block of the periodic table is a set of elements unified by the atomic orbitals their valence electrons or vacancies lie in. The term seems to have been first used by Charles Janet. Each block is named after its characteristic orbital: s-bl ...

, a block of elements in the periodic table of elements * F (or Phe), abbreviation for compound

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the chemical formula, formula . It can be viewed as a benzyl group substituent, substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of ...

Biology

Form (botany) In botanical nomenclature, a ''form'' (''forma'', plural ''formae'') is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon. If more than three ranks are listed i ...

Form (zoology) In zoology, the word "form" or "''forma''" (literally Latin for ''form'') is a strictly informal term that is sometimes used to describe organisms. Under the ''International Code of Zoological Nomenclature'' the term has no standing (it is not ac ...

Bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

, which is expressed as the letter "F" in medical chemistry equations * Haplogroup F (Y-DNA), a patrilineal haplogroup * Haplogroup F (mtDNA), a matrilineal haplogroup

Music

F (musical note) F is a musical note, the fourth above C or fifth below C. It is the fourth note and the sixth semitone of the solfège. It is also known as fa in fixed-do solfège. It is enharmonic equivalent with E (E-sharp) and G (G-double flat), amongs ...

F major F major is a major scale based on F, with the pitches F, G, A, B, C, D, and E. Its key signature has one flat.Music Theory'. (1950). United States: Standards and Curriculum Division, Training, Bureau of Naval Personnel. 28. Its relati ...

, a scale * F minor, a scale * F major chord, Chord names and symbols (popular music) * f,

Forte (music) In music, the dynamics of a piece are the variation in loudness between note (music), notes or phrase (music), phrases. Dynamics are indicated by specific musical notation, often in some detail. However, dynamics markings require interpretation ...

* ''F'' (album), an album by Japanese singer Masaharu Fukuyama *'' F Album'', an album by Japanese duo KinKi Kids *"F", song on the double A-side single " Tsume Tsume Tsume/F" by Japanese metal band Maximum the Hormone

Transport

* F Sixth Avenue Local, a rapid transit service of the New York City Subway * F (S-train), trains on the ring line of Copenhagen's commuter train network *

F Market & Wharves The F Market & Wharves line is one of several light rail lines in San Francisco, California. Unlike most other lines in the system, the F line runs as a heritage streetcar service, almost exclusively using historic equipment from San Francisco' ...

, a heritage streetcar line operated by the San Francisco Municipal Railway *

Tokyo Metro Fukutoshin Line The , formally the , is a subway line operated by Tokyo Metro in west-central Tokyo and Wako, Saitama, Japan. The newest line in the Tokyo subway network, it opened in stages between 1994 and 2008. On average, the Fukutoshin Line carried 362,654 ...

, a subway service operated by the Tokyo Metro, labeled Logo of Tokyo Metro Fukutoshin Line

* The NYSE ticker symbol of the

Ford Motor Company Ford Motor Company (commonly known as Ford) is an American multinational corporation, multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. T ...

, the official West Japan Railway Company service symbol for the Osaka Higashi Line. *

Ford F-Series The Ford F-Series is a series of light-duty trucks marketed and manufactured by Ford Motor Company since model year 1948 as a range of full-sized pickup trucks — positioned between Ford's Ford Ranger (T6), Ranger and Ford Super Duty, ...

, a series of full-size pickup trucks from Ford Motor Company

Military

* F, a class of designation in the United States military aircraft designation systems which stands for "Fighter" * F, a common designation for

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

Foxtrot The foxtrot is a smooth, progressive dance characterized by long, continuous flowing movements across the dance floor. It is danced to big band (usually vocal) music. The dance is similar in its look to waltz, although the rhythm is in a time ...

, the military time zone code for UTC+06:00 * F band (NATO), a radio frequency band from 3 to 4 GHz

Other uses

* ''F'' (film), a 2010 film directed by Johannes Roberts * France, on the vehicle registration plates of the European Union * F (grade), a failing grade * f, the symbol used in the International Phonetic Alphabet for the

voiceless labiodental fricative The voiceless labiodental fricative is a type of consonantal sound used in a number of spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is . Some scholars also posit the voiceless labiodental approx ...

* f, common abbreviation in lexicons meaning ''feminine

grammatical gender In linguistics, a grammatical gender system is a specific form of a noun class system, where nouns are assigned to gender categories that are often not related to the real-world qualities of the entities denoted by those nouns. In languages wit ...

'' * Fax, referring to a facsimile machine * F, abbreviation for fax number * The citation abbreviation of the ''

Federal Reporter The ''Federal Reporter'' () is a case law reporter in the United States that is published by West Publishing and a part of the National Reporter System. It begins with cases decided in 1880; pre-1880 cases were later retroactively compiled b ...

'' * F, Fujitsu's mobile phones in Japan * Forward position in Australian Rules football * "F" or "F***", sometimes used to censor "

fuck ''Fuck'' () is profanity in the English language that often refers to the act of sexual intercourse, but is also commonly used as an intensifier or to convey disdain. While its origin is obscure, it is usually considered to be first attested ...

". * f, abbreviation for the social networking service

Facebook Facebook is a social media and social networking service owned by the American technology conglomerate Meta Platforms, Meta. Created in 2004 by Mark Zuckerberg with four other Harvard College students and roommates, Eduardo Saverin, Andre ...

* Common abbreviation for

floor A floor is the bottom surface of a room or vehicle. Floors vary from wikt:hovel, simple dirt in a cave to many layered surfaces made with modern technology. Floors may be stone, wood, bamboo, metal or any other material that can support the ex ...

(for example, "3F" = 3rd floor) * F word (disambiguation), euphemism for several words beginning with "f" * Dominical letter F for a

common year starting on Tuesday A common year starting on Tuesday is any non-leap year (i.e. a year with 365 days) that begins on Tuesday, 1 January, and ends on Tuesday, 31 December. Its dominical letter hence is F. The most recent year of such kind was 2019, and the next one wi ...

* F, as an online expression of respects to a recently deceased person (as a reference to the videogame ''Call of Duty: Advanced Warfare'') *F, the production code for the 1964 ''Doctor Who'' serial '' The Aztecs'' * '' "F" Is for Fugitive'', the sixth novel in Sue Grafton's "Alphabet mystery" series, published in 1989