Definify.com
Webster 1913 Edition
Moonfish
Moon′fishˊ
,Noun.
 (Zool.) 
(a) 
An American marine fish (
Vomer setipennis
); – called also bluntnosed shiner
, horsefish
, and sunfish
. (b) 
A broad, thin, silvery marine fish (
Selene vomer
); – called also lookdown
, and silver moonfish
. (c) 
The mola. See 
Sunfish
, 1.