Floun″der (?), n. [Cf. Sw. flundra; akin to Dan. flynder, Icel. fly�ra, G. flunder, and perh. to E. flounder, v.i.] 1. (Zoöl.) A flatfish of the family Pleuronectidæ, of many species.
☞ The common English flounder is Pleuronectes flesus. There are several common American species used as food; as the smooth flounder (P. glabra); the rough or winter flounder (P. Americanus); the summer flounder, or plaice (Paralichthys dentatus), Atlantic coast; and the starry flounder (Pleuronectes stellatus).
2. (Bootmaking) A tool used in crimping boot fronts.