- [Zoöl] A genus of large American serpents, including the boa constrictor, the emperor boa of Mexico (Boa imperator), and the chevalier boa of Peru (Boa eques).
- A long, round fur tippet; -- so called from its resemblance in shape to the boa constrictor.
Note: ☞ The name is also applied to related genera; as, the dog-headed boa Xiphosoma caninum).
Etymology: L. boa a kind of water serpent. Perh. fr. bos an ox