Toadfish \Toad"fish`\, n. (Zo["o]l.) (a) Any marine fish of the genus {Batrachus}, having a large, thick head and a wide mouth, and bearing some resemblance to a toad. The American species ({Batrachus tau}) is very common in shallow water. Called also {oyster fish}, and {sapo}. (b) The angler. (c) A swellfish.