cavern
1. cav.ern \'kav-*rn\ n [ME caverne, fr. MF, fr. L caverna, fr. cavus] : an underground chamber often of large or indefinite extent : CAVEM 2. cavern vt 1: to place in or as if in a cavern 2: to form a cavern of : HOLLOW - used with out
Webster's English Dictionary1. cav.ern \'kav-*rn\ n [ME caverne, fr. MF, fr. L caverna, fr. cavus] : an underground chamber often of large or indefinite extent : CAVEM 2. cavern vt 1: to place in or as if in a cavern 2: to form a cavern of : HOLLOW - used with out