Bateau \Ba*teau"\, n.; pl. Bateaux. [F. bateau, LL. batellus, fr. battus, batus, boa, which agrees with AS. b[=a]t boat: cf. W. bad boat. See Boat, n.]

A boat; esp. a flat-bottomed, clumsy boat used on the Canadian lakes and rivers. [Written also, but less properly, batteau.]

Bateau bridge, a floating bridge supported by bateaux.

Source: Webster's Revised Unabridged Dictionary (1913)