Source : Webster's Revised Unabridged Dictionary (1913)

Diodon \Di"o*don\, n. [Gr. di- = di`s- twice + ?, ?, a tooth:
   cf. F. diodon.]
   1. (Zo["o]l.) 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. (Zo["o]l.) A genus of whales.

Source : WordNet®

swellfishes
     See {swellfish}