F/V alternationThere is sometimes an alternation between f and v in grammatically or etymologically related words. For example, the following nouns have singular -f(e), plural -ves: calf, elf, half, knife, leaf, life, loaf, self, sheaf, shelf, thief, wife, wolf. In some cases, the plural may be either -fs or -ves: dwarfs/dwarves, hoofs/hooves. So engrained is the tendency to f/v alternation that handkerchiefs, roofs are often pronounced with /v/. Verbs from such nouns have f or v, but do not vary when inflected: to knife/knifed, to halve/halved. Other examples of v/f alternation include believe/belief, leave/left, strive/strife, five/fifth, twelve/twelfth. The f/v distinction in fox/vixen arises from the different dialects from which the words have been taken.
Double F(1) Except in if, of and some loanwords, f is doubled in syllable-final position immediately after a single vowel letter that is pronounced short: waffle, piffle, bailiff, cliff, scoff, stuff. Single f occurs otherwise: deaf, elf, beef, belief, dwarf, golf, loaf. (2) There is doubling between vowels, especially to show the assimilation of the Latin prefixes ad-, ob-, sub-, as in affair, offer, suffer. An anomaly is single f in afraid, despite ff in the related affray.
F, GH, and PH.(1) In some common words, the digraph gh represents /f/: cough, enough, laugh, rough, tough. AmE does not make the BrE distinction between draught/draft, having draft for both. In BrE, a draftsman draws up the wording of documents and a draughtsman prepares technical drawings. See G. (2) The digraph ph represents /f/, generally in words of Greek origin: photograph, philosophy. See P. F has, however, varied historically with ph in some words: for example, with the revival of Greek learning in the 16c, fantasy began to be written phantasy, but in the 20c has reverted to f. Occasionally, words not derived from Greek have acquired ph in place of f: nephew was once written with both f and v. AmE sulfur retains the original Latin form, whereas BrE has sulphur; the AmE form is increasingly used internationally, as for example by pure and applied chemists. In commerce, a standard ph may be replaced by f in a trade name or for special effect, or both, as with fotopost and freefone. See WRITING.
F1 / ef/ (also f) • n. (pl. Fs or F's) 1. the sixth letter of the alphabet. ∎ denoting the next after E in a set of items, categories, etc. ∎ the sixth highest or lowest class of academic marks (also used to represent “Fail”).2. (usu. F) Mus. the fourth note of the diatonic scale of C major. ∎ a key based on a scale with F as its keynote.F2 • abbr. ∎ Fahrenheit: 60°F. ∎ failure. ∎ false. ∎ farad(s). ∎ Chem. faraday(s). ∎ February. ∎ Fellow. ∎ female. ∎ fighter (in designations of U.S. aircraft types): the F117 Stealth fighter. ∎ forint. ∎ Franc(s). ∎ France. ∎ French.• symb. ∎ the chemical element fluorine. ∎ Physics force: F = ma.
f • abbr. ∎ farad. ∎ farthing. ∎ father. ∎ fathom. ∎ feet. ∎ Gram. feminine. ∎ female. ∎ [in comb.] (in units of measurement) femto- (10−15). ∎ filly. ∎ fine. ∎ (in textual references) folio. ∎ following. ∎ foot. ∎ form. ∎ Mus. forte. ∎ (in racing results) furlong(s). ∎ franc. ∎ from. ∎ Chem. denoting electrons and orbitals possessing three units of angular momentum: f-orbitals.• symb. ∎ focal length: apertures of f/5.6 to f/11. See also f-number. ∎ Math. a function of a specified variable: the value of f(x). ∎ Electr. frequency.
• Music fah (in tonic sol-fa)
• symbol for femto- (prefix indicating 10-15, as in fm, femtometre)
• (or f/, f:) Photog. f-number (ratio of the focal length of a lens to its aperture, as in f8)
• (ital.) Physics, symbol for focal length
• (ital.) Music forte (Italian; loudly)
• (ital.) Physics, symbol for frequency
• (ital.) Physical chem., symbol for fugacity
• (ital.) Maths., symbol for function (as in f(x))
• (ital.) Biochem., symbol for furanose
• Chem., Physics, indicating electron state l=3 (where l is orbital angular momentum quantum number)
• indicating the fifth vertical row of squares from the left on a chessboard