Source : Webster's Revised Unabridged Dictionary (1913)

Hazelnut \Ha"zel*nut`\, n. [AS. h[ae]selhnutu.]
   The nut of the hazel. --Shak.

Source : WordNet®

hazelnut
     n 1: any of several shrubs or small trees of the genus Corylus
          bearing edible nuts enclosed in a leafy husk [syn: {hazel},
           {hazelnut tree}]
     2: nut of any of several trees of the genus Corylus [syn: {filbert},
         {cobnut}, {cob}]