a silverside fish (Leuresthes tenuis) of the California coast: it spawns on sandy beaches during high tides in the spring
Origin:
prob. < Sp gruñón, grumbler < L grunnire, to grunt < IE *gru-, echoic
See grunion in American Heritage Dictionary 4
noun
A small fish (Leuresthes tenuis) of coastal waters of California and Mexico that spawns at night along beaches during the high tides of spring and summer.