Plaice \Plaice\, n. [F. plaise, plais, prob. fr. L. platessa flatish, plaice. See Place.]

(Zo["o]l.)
   (a) A European food fish (Pleuronectes platessa), allied to the flounder, and growing to the weight of eight or ten pounds or more.
   (b) A large American flounder (Paralichthys dentatus; called also brail, puckermouth, and summer flounder. The name is sometimes applied to other allied species. [Written also plaise.]

Plaice mouth, a mouth like that of a plaice; a small or wry mouth. [R.]

--B. Jonson.

Source: Webster's Revised Unabridged Dictionary (1913)