To Cave

1. To surrender.
2. To collapse.
3. To hollow out or undermine.
4. To engage in the recreational exploration of caves. Synonym: spelunk
5. (mining) In room-and-pillar mining, to extract a deposit of rock by breaking down a pillar which had been holding it in place.
6. (mining, obsolete) To work over tailings to dress small pieces of marketable ore.
7. (obsolete) To dwell in a cave.