Gruta, subterrâneo, biboca, antro, solapar, caverna.n.
To make hollow; to scoop out.
To dwell in a cave.
To fall in or down; as, the sand bank caved. Hence (Slang), to retreat from a position; to give way; to yield in a disputed matter
geological formation generic term, formation generic term verb, undermine, hollow generic term, hollow out generic term, core out generic term verb, spelunk, explore generic term