noun, feminine/bɛʁ.naʃ/plural: bernaches
brant, barnacle goose; any goose of the genus Branta; grape juice at the beginning of its fermentation process
From Old French (Norman-Picard) bernaque, bernicle (1270), from Gaulish *bernacula "barnacle" (cf. Irish bairneach, Breton and Welsh brennig), from *barenos "rock" (cf. Irish barenn). The sense evolution is due to the popular belief that barnacle geese, a type of brant, were born out of barnacles (the sea creature).