'Hazelnut' definitions:

Definition of 'hazelnut'

noun

Any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk [syn: hazelnut, hazel, hazelnut tree]

noun

Nut of any of several trees of the genus Corylus [syn: hazelnut, filbert, cobnut, cob]

From: GCIDE

Hazelnut \Ha"zel*nut`\ (h[=a]"z'l*n[u^]t`), n. [AS. h[ae]selhnutu.] The nut of the hazel. --Shak. [1913 Webster]