TRAP, n. In mineralogy, a name given to rocks characterized by a columnar form, or whose strata or beds have the form of steps or a series of stairs. Kirwan gives this name to two families of basalt. It is now employed to designate a rock or aggregate in which hornblend predominates, but it conveys no definite idea of any one species; and under this term are comprehended hornblend, hornblend slate, greenstone, greenstone slate, amygdaloid, basalt, wacky, clinkstone porphyry, and perhaps hypersthene rock, augite rock, and some varieties of sienite.
TRAP, v.t. To catch in a trap; as, to trap foxes or beaver.
TRAP, v.i. To set traps for game; as, to trap for beaver.