F5U may refer to
5-FU or f5U, technical name of the drug Fluorouracil uranium pentafluoride (F5U), see Glossary of chemical formulae Vought XF5U "Flying Flapjack", experimental U.S. Navy fighter aircraft F5u, a type of German torpedo, see List of World War II torpedoes of Germany
See also
FSU (disambiguation) FVU (disambiguation) FU (disambiguation)