Definition of rock cook in US English:

rock cook

noun

  • A small wrasse, Centrolabrus exoletus, found off northern European coasts and occasionally in intertidal pools.

Origin

Mid 19th century; earliest use found in Magazine of Natural History. From rock + a second element of uncertain origin, perhaps a borrowing from Cornish kôg cuckoo; compare cuckoo, cuckoo-wrasse, and cook-wrasse, all denoting kinds of wrasse.

Pronunciation

rock cook

/ˈrɒk kʊk/