The Collaborative International Dictionary of English v.0.48:

Hamamelis \Ham`a*me"lis\ (h[a^]m`[.a]*m[=e]"l[i^]s), n. [NL.,
   fr. Gr. "amamhli`s a kind of medlar or service tree; "a`ma at
   the same time + mh^lon an apple, any tree fruit.] (Bot.)
   A genus of plants which includes the witch-hazel (Hamamelis
   Virginica), a preparation of which is used medicinally.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Hamamelis
    n 1: deciduous shrubs or small trees: witch hazel [syn:
         Hamamelis, genus Hamamelis]