The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
noun pl. tonguefish or tongue·fish·es
Any of various marine flatfishes of the family Cynoglossidae, having the posterior part of the body tapering to a point.
Origin: From its tongue-shaped body.