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 *

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 distribution ...

, a continuous probability distribution **

F-test An ''F''-test is any statistical test in which the test statistic has an ''F''-distribution under the null hypothesis. It is most often used when comparing statistical models that have been fitted to a data set, in order to identify the model ...

, 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 or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The pre ...

, factor 10⁻¹⁵ * ,

Fibonacci number In mathematics, the Fibonacci numbers, commonly denoted , form a sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start the sequence from ...

Computing and engineering

* F (programming language), a subset of Fortran 95 * F Sharp (programming language), a functional and object-oriented language for the .NET platform. *

F* (programming language) F* (pronounced ''F star'') is a functional programming language inspired by ML and aimed at program verification. Its type system includes dependent types, monadic effects, and refinement types. This allows expressing precise specifications ...

, 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 that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can b ...

* F connector, used for inlet in cable modems *

F crimp F-Crimp is a type of solderless electrical crimp connection. It is not related to the F connector common in RF equipment. It is sometimes referred to as ''open-barrel'', which is technically a more general term including crimp types such as ''Weat ...

, a type of solderless electrical connection * F band (NATO), a radio frequency band from 3 to 4 GHz *

F band (waveguide) The waveguide F band is the range of radio frequencies from 90 GHz to 140 GHz in the electromagnetic spectrum, corresponding to the recommended frequency band of operation of WR8 waveguides. These frequencies are equivalent to wave le ...

, a millimetre wave band from 90 to 140 GHz

Physics

* °F, degree on the

Fahrenheit The Fahrenheit scale () is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined hi ...

temperature scale * F, for farad, a unit for electric capacitance * or ℱ, the

Faraday constant In physical chemistry, the Faraday constant, denoted by the symbol and sometimes stylized as ℱ, is the electric charge per mole of elementary charges. It is named after the English scientist Michael Faraday. Since the 2019 redefinition of ...

* , focal length of a lens **

f-number In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill Pro ...

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

\vec F

, , , force * ,

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

* 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 ener ...

* ''F'', the electromagnetic field tensor in electromagnetism *: Often generalized to include the field tensors of other interactions, as in i.e. the gluon field strength tensor. * F region, part of the ionosphere

Chemistry

* Fluorine, symbol F, a chemical element * f-block, a block of elements in the periodic table of elements * F (or Phe), abbreviation for compound phenylalanine

Biology

* Form (botany) * Form (zoology) *

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%. Ho ...

, 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 has enharmonic equivalents of E (E-sharp) and G (G-double flat), amongst ...

F major F major (or the key of F) is a major scale based on F, with the pitches F, G, A, B, C, D, and E. Its key signature has one flat. Its relative minor is D minor and its parallel minor is F minor. The F major scale is: : F major is the ...

, a scale *

F minor F minor is a minor scale based on F, consisting of the pitches F, G, A, B, C, D, and E. Its key signature consists of four flats. Its relative major is A-flat major and its parallel major is F major. Its enharmonic equivalent, E-sharp mi ...

, a scale * F major chord,

Chord names and symbols (popular music) Musicians use various kinds of chord names and symbols in different contexts to represent musical chords. In most genres of popular music, including jazz, pop, and rock, a chord name and its corresponding symbol typically indicate one or more ...

* f, Forte (music) * ''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) F is the service designation for trains on the ring line of Copenhagen's S-train network. It runs from about 05:00 to 01:00 from Ny Ellebjerg to Hellerup. Trains run every 5 minutes between about 7:00 and 19:00, Monday through Friday, and eve ...

, 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 both from San Franc ...

, a heritage streetcar line operated by the San Francisco Municipal Railway * The NYSE ticker symbol of the

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

Ford F-Series The Ford F-Series is a series of light-duty trucks marketed and manufactured by Ford Motor Company, Ford since the 1948 model year. Slotted above the Ford Ranger (Americas), Ford Ranger in the Ford truck model range, the F-Series is market ...

, 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 Multiple designation systems have been used to specify United States military aircraft. The first was designed in 1919 when the US Army's Aeronautical Division became the United States Army Air Service. Before this, aircraft were put into service un ...

which stands for "Fighter" * F, a common designation for fighter aircraft * Foxtrot, 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 France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

, on the

vehicle registration plates of the European Union A vehicle registration plate, also known as a number plate (British English), license plate or licence plate ( American English and Canadian English respectively), is a metal or plastic plate or plates attached to a motor vehicle or trailer for ...

* 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, grammatical gender system is a specific form of noun class system, where nouns are assigned with gender categories that are often not related to their real-world qualities. In languages with grammatical gender, most or all noun ...

'' *

Fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...

, 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 by We ...

'' * F, Fujitsu's mobile phones in Japan * Forward position in Australian Rules football * "F" or "F***", sometimes used to censor " fuck". * f, abbreviation for the social networking service

Facebook Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin Mosk ...

* Common abbreviation for floor (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 * 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