Definition of minnow

• n. - A small European fresh-water cyprinoid fish (Phoxinus laevis, formerly Leuciscus phoxinus); sometimes applied also to the young of larger kinds; -- called also minim and minny. The name is also applied to several allied American species, of the genera Phoxinus, Notropis, or Minnilus, and Rhinichthys.
• n. - Any of numerous small American cyprinodont fishes of the genus Fundulus, and related genera. They live both in fresh and in salt water. Called also killifish, minny, and mummichog.