witch hazel noun6 •Any of several small deciduous trees, of the genus Hamamelis, having yellow flowers •An extract of the bark and/or leaves of this plant, used as an astringent •Hamamelis virginiana, native to eastern North America. •(US) Hamamelis vernalis, native to the Ozarks. •(no longer used) A wych-elm, or a certain subspecies of it distinguished from wych-elm. •(no longer used) Hornbeam (Carpinus betulus). formswitch hazels