The Collaborative International Dictionary of English v.0.48:

Hazel \Ha"zel\ (h[=a]"z'l), n. [OE. hasel, AS. h[ae]sel; akin to
   D. hazelaar, G. hazel, OHG. hasal, hasala, Icel. hasl, Dan &
   Sw. hassel, L. corylus, for cosylus.]
   1. (Bot.) A shrub or small tree of the genus Corylus, as
      the Corylus avellana, bearing a nut containing a kernel
      of a mild, farinaceous taste; the filbert. The American
      species are Corylus Americana, which produces the common
      hazelnut, and Corylus rostrata. See Filbert. --Gray.
      [1913 Webster]

   2. A miner's name for freestone. --Raymond.
      [1913 Webster]

   Hazel earth, soil suitable for the hazel; a fertile loam.


   Hazel grouse (Zool.), a European grouse (Bonasa
      betulina), allied to the American ruffed grouse.

   Hazel hoe, a kind of grub hoe.

   Witch hazel. See Witch-hazel, and Hamamelis.
      [1913 Webster]

WordNet (r) 3.0 (2006):

witch hazel
    n 1: any of several shrubs or trees of the genus Hamamelis; bark
         yields an astringent lotion [syn: witch hazel, witch
         hazel plant, wych hazel, wych hazel plant]
    2: lotion consisting of an astringent alcoholic solution
       containing an extract from the witch hazel plant [syn: witch
       hazel, wych hazel]