Di"o*don (?), n. [Gr. di- = di`s- twice + 'odoy`s, 'odo`ntos, a tooth: cf. F. diodon.] 1. (Zoöl.) A genus of spinose, plectognath fishes, having the teeth of each jaw united into a single beaklike plate. They are able to inflate the body by taking in air or water, and, hence, are called globefishes, swellfishes, etc. Called also porcupine fishes, and sea hedgehogs.

2. (Zoöl.) A genus of whales.