fi

noun[in compounds]3

1. •
   The solfeggio syllable used to indicate the sharp of the fourth note of a major scale.
2. •
   Abbreviation of fidelity (e.g. in hi-fi, lo-fi, or wi-fi).
3. •
   Abbreviation of fiction (e.g. in sci-fi).

noun4

1. •
   Initialism of fuel injection.
2. •
   Abbreviation of factor I (clotting factor I).
3. •
   Initialism of field interview/interrogation.
4. •
   Initialism of fault indicator.