Main definitions of f in English

: f1F2F3



  • 1Grammar

  • 2in combination (in units of measurement) femto- (10⁻¹⁵)

    ‘the detection limits of the enzymatic activity tests are between 10 and 500 fg per test’
  • 3(in textual references) folio.

  • 4Music

  • 5(in racing results) furlong(s)

    ‘2 m 3 f’
  • 6Chemistry
    Denoting electrons and orbitals possessing three units of angular momentum.


  • 1Focal length.

    ‘apertures of f/5.6 to f/11’
    See also f-number
  • 2Mathematics
    A function of a specified variable.

    ‘the value of f(x)’
  • 3Electronics

Main definitions of f in English

: f1F2F3



  • 1Fahrenheit.

  • 2Farad(s).

  • 3"F"Chemistry

  • 4(in racing results) favourite.

    ‘2nd Miss Prism 2–1 F’
  • 5Female.

  • 6Fighter (in designations of US aircraft types)

    ‘the F117 Stealth fighter’
  • 7Biology
    Filial generation.

  • 8British Fine (used in describing grades of pencil lead)

    ‘an F pencil’
  • 9(in motor racing) formula.

    ‘an F1 driver’
  • 10Franc(s)

    ‘$1.00 = F5.9645 as at April 29’
  • 11France (international vehicle registration).

  • 12(in tables of sports results) goals or points for.

  • 1The chemical element fluorine.

  • 2Physics





Main definitions of f in English

: f1F2F3


(also f)


  • 1The sixth letter of the alphabet.

    1. 1.1 Denoting the next after E in a set of items, categories, etc.
    2. 1.2 The sixth highest or lowest class of academic marks (also used to represent ‘Fail’)
      ‘they are guaranteed F's if they goof around’
      • ‘In the schools I went to, when you get that many Fs, you flunk out.’
      • ‘Moreover, not only Fs but also Ds are frowned on, and grades are regularly inflated to achieve C averages.’
    3. 1.3"f"Chess Denoting the sixth file from the left, as viewed from White's side of the board.
      • ‘Black has no way to oppose the Rooks on the f-file.’
      • ‘I don't like black's vulnerable f file or e5 pawn however.’
  • 2usually "F"Music
    The fourth note of the diatonic scale of C major.

    1. 2.1 A key based on a scale with F as its keynote.
      • ‘The key of F is found most commonly in folk-oriented music.’