Biology and medicine •
Feminization laryngoplasty, gender-affirming surgery to raise the pitch of the voice •
FLT3LG (Fms-related tyrosine kinase 3 ligand), a protein •
Fluffy transcription factor, gene of
Neurospora crassa • Fluorouracil (5-FU), and leucovorin (folinic acid), a
chemotherapy regimen •
Follicular lymphoma in medicine •
Frontal lobe, the largest brain lobe
Mathematics and computing •
FL (complexity), a class of functions •
FL (programming language) •
FL Studio, music production software
Other uses in science and technology •
Femtolitre, a unit of volume •
Flerovium, symbol Fl, a chemical element (atomic number 114) •
Flight level, of an aircraft • "Fluid", as in
fluid ounce (fl oz) •
Foot-lambert, a unit of luminance •
Friedmann–Lemaître metric in cosmology ==Sport==