conjunction \ˈif-ən(d)-ˈōn-lē-ˌif; ˈif, sometimes read with a prolonged f\

Definition of IFF

:  if and only if <two figures are congruent iff one can be placed over the other so that they coincide>

Origin of IFF

alteration of 1if
First Known Use: 1955



Definition of IFF

identification, friend or foe


Next Word in the Dictionary: iffen
Previous Word in the Dictionary: -iferous
All Words Near: iff

Seen & Heard

What made you want to look up iff? Please tell us where you read or heard it (including the quote, if possible).

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More