The fruit of the Corylus Avellana or Corylus maxima, also called the hazel; the hazelnut. It is an oval nut, containing a kernel that has a mild, farinaceous, oily taste, agreeable to the palate. [1913 Webster]
The tree bearing the filbert; the hazelnut tree. [PJC]
Filbert gall(Zoöl.), a gall resembling a filbert in form, growing in clusters on grapevines. It is produced by the larva of a gallfly (Cecidomyia).