noun, plural (especially collectively) moon·fish, (especially referring to two or more kinds or species) moon·fish·es.
  1. Also called horsefish, horsehead. any of several silvery marine fishes of the genus Selene, having a very compressed body and inhabiting shallow coastal waters.
  2. the opah.
  3. any of various other rounded, silvery fishes.

Origin of moonfish

First recorded in 1640–50; moon + fish Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for moonfish


noun plural -fishes or -fish
  1. any of several deep-bodied silvery carangid fishes, occurring in warm and tropical American coastal waters
  2. any of various other round silvery fishes, such as the Indo-Pacific Monodactylus argenteus
  3. another name for opah
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012