noun: (informal) An uncertainty, possibility, condition, doubt etc.
noun: Initialism of interactive fiction. [(literature, uncountable) Text adventures and their descendants.]
noun: Initialism of impact factor. [A measure reflecting the average number of citations to recent articles published in an academic journal, used as an approximation of the relative importance of a journal within its field.]
noun: (biochemistry) Initialism of intermediate filament. [(biochemistry) Any of a family of twisted protein filaments intermediate in size between microfilaments and microtubules.]
noun: (electronics) Initialism of intermediate frequency. [(radio) A frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception; generally associated with superheterodyne receivers.]