Latin word beccus comes from Proto-Indo-European *baḱ-, and later Proto-Celtic *bekkos (Beak, snout.)

Detailed word origin of beccus

Dictionary entry	Language	Definition
*baḱ-	Proto-Indo-European (ine-pro)
*bekkos	Proto-Celtic (cel-pro)	Beak, snout.
*bekkos	Gaulish (cel-gau)
beccus	Latin (lat)	Beak, bill (especially of a cock).