Definition of king mackerel in English:

king mackerel

noun

  • Any of several large mackerels of the genus Scomberomorus; (in later use) specifically a large mackerel, Scomberomorus cavalla, found in the western Atlantic Ocean and Gulf of Mexico and valued as a food fish; also called kingfish.

Origin

Late 19th century; earliest use found in Lippincott's Monthly Magazine.