Definition of mackerel
plural mackerel
or mackerels
1
: a scombroid fish (Scomber scombrus of the family Scombridae) of the North Atlantic that is green above with dark blue bars and silvery below and is a commercially important food fish
2
: any of various fishes (such as the wahoo and king mackerel) in the same family as the mackerel especially when distinguished from the related bonito or tuna by a comparatively smaller size
