Boa \Bo"a\, n.; pl. Boas . [L. boa a kind of water serpent. Perh. fr. bos an ox.]

1. (Zo["o]l.) A genus of large American serpents, including the boa constrictor, the emperor boa of Mexico (B. imperator), and the chevalier boa of Peru (B. eques).

Note: The name is also applied to related genera; as, the dog-headed boa (Xiphosoma caninum).

2. A long, round fur tippet; -- so called from its resemblance in shape to the boa constrictor.

Source: Webster's Revised Unabridged Dictionary (1913)