iff

I1F4F4
UK/ɪf ən(d)ˈəʊn.li ɪf/US/ɪf ən(d)ˈoʊn.li ɪf/

Abbreviation of if and only if.

Less commonScrabble 9
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Meanings

iff1

conjunction
  1. abbreviationhuman sciencesAbbreviation of if and only if.

    A rectangle is a square iff all four of its sides have the same length.

iff2

conjunction
  1. obsoleteObsolete spelling of if.

    For iff the patient be aſhamed to diſcloſe hiſ wounde to the phyſician which knoweth it not , phyſicke can not helpe him.

    1565, Thomas Stapleton, A Fortreſſe of the Faith &c., Ihon Laet, the 2. part. 112

IFF3

proper noun
  1. abbreviationinitialismfile formatInitialism of Interchange File Format, a file format standard developed for Amiga computers.
  2. abbreviationinitialismInitialism of International Flavors & Fragrances
noun
  1. abbreviationinitialismInitialism of identification friend or foe.

    IFF confirmed. Contact is Pelican Dropship Kilo 23. Over.

    2007 September 25, Bungie, Halo 3, Microsoft Game Studios, Xbox 360, level/area: Sierra 117
    1 more example

    Another red alert last night. Lasted only five minutes, Possibly just a friendly plane with its IFF turned off.

    1944 August 7, Charles A. Lindbergh, The Wartime Journals of Charles A. Lindbergh, New York: Harcourt Brace Jovanovich, published 1970, page 898

ifF4

proper noun
  1. UKabbreviationinitialismgovernmentInitialism of Independents for Frome.

Synonyms & antonyms

Also see
identification friend or foe

Translations

Danish hviss
  • hvissabbreviation of if and only if
Dutch desda
  • desdaabbreviation of if and only if
Finnish joss
  • jossabbreviation of if and only if
French ssi
  • ssiabbreviation of if and only if
German gdw.
  • gdw.abbreviation of if and only if
Hebrew אםם
  • אםםabbreviation of if and only if
Hungarian acsa
  • acsaabbreviation of if and only if
Italian sse
  • sseabbreviation of if and only if
Norwegian hviss
  • hvissabbreviation of if and only if
Polish wtw
  • wtwabbreviation of if and only if
Portuguese sse, sss
  • sseabbreviation of if and only if
  • sssabbreviation of if and only if
Romanian ddacă
  • ddacăabbreviation of if and only if
Russian титтк
  • титтк (tittk)abbreviation of if and only if
Spanish sii
  • siiabbreviation of if and only if
Swedish omm
  • ommabbreviation of if and only if
Cite this entry
APA

iff. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/iff

MLA

“iff.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/iff. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “iff,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/iff.

Source: iff on Wiktionary, CC BY-SA 4.0.