Floun·der n.
1. Zool. A flatfish of the family Pleuronectidæ, of many species.
Note: ☞ 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.