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2017 Word of the Year

iff

Mathematics.
1.
if and only if.

IFF

Military.
1.
Identification, Friend or Foe: a system of transmitters and transponders that uses coded signals to distinguish between friendly and hostile aircraft.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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Examples from the Web for iff
Contemporary Examples
Historical Examples
  • I could like her better, iff she was better to my young lady.

    Clarissa, Volume 3 (of 9) Samuel Richardson
  • But that same reseit, iff your Honner so please, to cure a shrewish wife.

    Clarissa, Volume 3 (of 9) Samuel Richardson
  • And what wold ye doe with my bryde soe gay, iff I did sell her thee?

  • Mr. iff enquired in simple surprise: “Do you really care to know?”

    The Bandbox Louis Joseph Vance
  • Mr. Staff, I want you to shake hands with my friend, Mr. iff.

    The Bandbox Louis Joseph Vance
  • It was, in fact, the bandbox which had first fixed the interest of Mr. iff.

    The Bandbox Louis Joseph Vance
  • “He has his troubles,” quoth Mr. iff cheerfully, if vaguely.

    The Bandbox Louis Joseph Vance
  • iff elevated one of the glasses which had just been put before them.

    The Bandbox Louis Joseph Vance
  • I beg your pardon,” said the person addressed, icily; “my name is iff.

    The Bandbox Louis Joseph Vance
British Dictionary definitions for iff

iff

/ɪf/
conjunction
1.
(logic) a shortened form of if and only if: it indicates that the two sentences so connected are necessary and sufficient conditions for one another. Usually iff is used for equivalence in the metalanguage, rather than as the biconditional in the object language

IFF

abbreviation
1.
Identification, Friend or Foe: a system using radar transmissions to which equipment carried by friendly forces automatically responds with a precoded signal
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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