Definition of grunion
: a silverside (Leuresthes tenuis) of the California coast notable for the regularity with which it comes inshore to spawn at nearly full moon
Origin of grunion
probably from Spanish gruñón grunter
First Known Use: 1917
Learn More about grunion
Britannica.com: Encyclopedia article about "grunion"
Seen and Heard
What made you want to look up grunion? Please tell us where you read or heard it (including the quote, if possible).