chasm Play nounA deep fissure in the earth's surface. SYNONYMS abyssarroyobarrancabunnycanyoncavitychinecleftcleuchcloughcouleecouloircratercrevassecrevicedefiledongafissureflumegapgillgorgegulchgulfgullyheughholehollowkhorkhudkloofnullahopeningpasspitquebradaravinerentriftslootthrutchvoid