What is "swellfish"

Puffer \Puff"er\, n.

1. One who puffs; one who praises with noisy or extravagant commendation.

2. One who is employed by the owner or seller of goods sold at suction to bid up the price; a by-bidder.
   --Bouvier.

3. (Zo["o]l.)

   1. Any plectognath fish which inflates its body, as the species of Tetrodon and Diodon of the family Tetraodontidae; -- called also blower, puff-fish, swellfish, and globefish. They are highly poisonous due to the presence of glands containing a potent toxin, tetrodotoxin. Nevertheless they are eaten as a delicacy in Japan, being prepared by specially licensed chefs who remove the poison glands.

   2. The common, or harbor, porpoise.

4. (Dyeing) A kier.

Bur fish \Bur" fish`\ (Zo["o]l.) A spinose, plectognath fish of the Allantic coast of the United States (esp. Chilo mycterus geometricus) having the power of distending its body with water or air, so as to resemble a chestnut bur; -- called also ball fish, balloon fish, and swellfish.

n. (context zoology English) Any plectognath fish that dilates itself, such as the pufferfish.