franc 
(frăngk)
(frăngk)n. Abbr. F or fr.
1. See Table at currency.
2. The primary unit of currency in Belgium, France, Luxembourg, and Monaco before the adoption of the euro.
[Middle English frank, French gold coin, from Old French franc, from Medieval Latin Francōrum (rēx), (king) of the Franks (from the legend on the first of these coins), genitive pl. of Francus, Frank; see FRANK.]