DICT.TW Dictionary Taiwan

 Trap, n.  Geol. An old term rather loosely used to designate various dark-colored, heavy igneous rocks, including especially the feldspathic-augitic rocks, basalt, dolerite, amygdaloid, etc., but including also some kinds of diorite. Called also trap rock.
 Trap tufa, Trap tuff, a kind of fragmental rock made up of fragments and earthy materials from trap rocks.