Used other than figuratively or idiomatically: see hard, nut, crack. / (idiomatic) A problem that is challenging to solve.

plural of hard nut to crack

plural of harbor seal

plural of harbour seal

plural of hard copy

(originally Australia) The key effort in completing a difficult task.

Alternative form of harbourmaster

Alternative form of Jew's harp

American desert hare, Lepus californicus, the black-tailed jackrabbit. / Cape hare, Lepus capensis

A mechanical device that limits the travel of a mechanism. / A definite time when someone must end a task in order to meet another time commitment.