1British the tough-skinned larva of a large crane fly. It lives in the soil, where it feeds on plant matter and can seriously damage the roots of grasses and crops.
Genus Tipula, family Tipulidae
2any of a number of tough-skinned marine fishes, in particular:
a fish of the jack family (Carangidae), in particular a slender fish of American coastal waters, with a greenish back and a bright yellow tail (Oligoplites saurus).a filefish or triggerfish (family Balistidae).
leatherjacket in other Oxford dictionaries
Definition of leatherjacket in the US English dictionary