oiseau m (plural oiseaux)
From Old French oisel, from Late Latin aucellus, contraction of Vulgar Latin *avicellus, diminutive of Latin avis, from Proto-Italic *awis, from Proto-Indo-European *h₂éwis. Compare Italian uccello, Occitan aucèl, Catalan ocell, Walloon oujhea, Gallo ouézai, Jersey Norman ouaîsé, Franco-Provençal usél, Friulian uciel, Sicilian aceddu, Neapolitan auciello.
Compare also with oie (“goose”), itself derived from avis.