leather jack | Definition of leather jack

1a : a filefish (family Monacanthidae)

b or less commonly leather jack : any of several fishes (genus Oligoplites) of the family Carangidae having the scales reduced and embedded in the skin especially : a common fish (O. saurus) of both coasts of tropical America

2 : any of several Australian trees with very tough close smooth bark especially : coachwood sense 1a