a large animal of the cow family that has wide, curved horns. There are two types of buffalo, the African and the Asian. 水牛（分非洲水牛和亚洲水牛两种） 
a North American bison (= a large wild animal of the cow family that is covered with hair) 水牛（分非洲水牛和亚洲水牛两种）
Word Originmid 16th cent.: probably from Portuguese bufalo, from late Latin bufalus, from earlier bubalus, from Greek boubalos ‘antelope, wild ox’.