FU
FU is frequently used to mean follow‑up in medical notes, but it also appears in tech as file upload and colloquially to describe a foul‑up.
Medical
Miscellaneous
Formula Unit
Future Unit
Fluorescence Unit
Frag University
Funny Uncle
Fertilizer Use
Fearless Unit
Funky Underpants
Francis Urquhart
Freie Universität
Forever Unloved
Community
Governmental
Fire Unit
First User
Foul Up
Food Unit
Flight Unit
FUel
Farmacopea Ufficiale
Fart Underwater (submarine sound)
Academic & Science
Forecast Unit
Florida University
Fordham University
Furman University
Forces Unknown
Fraction Unbound
Feedback Unit
Finite Union
Friends University
Frost Up
Fude University