noun

• (caving) A naturally-occurring cavity in bedrock which is large enough to be entered by an adult.
  "It was not strictly a cave, but a narrow fissure in the rock."
• (nuclear physics) A shielded area where nuclear experiments can be carried out.
  "These potential radiation fields or radioactive material levels may be the result of normal operations (ie, radiation in a target cave) […]"
• (drilling, uncountable) Debris, particularly broken rock, which falls into a drill hole and interferes with drilling.
  "[…] the casing can then be placed in the hole without encountering any cave and core drilling in rock can begin."
• (mining) A collapse or cave-in.
  "The "breasts" of marble which unite the opposite lateral walls have been left standing in order to prevent a possible cave of the wall on either side."

verb

• (figurative) To surrender.
  "He caved under pressure."
• (mining) In room-and-pillar mining, to extract a deposit of rock by breaking down a pillar which had been holding it in place.
  "The deposit is caved by knocking out the posts."
• (mining, obsolete) To work over tailings to dress small pieces of marketable ore.
  "As an indication of the miners' desperation in these years, the free miners of Wensley lowered themselves to caving for scraps of ore."
• (obsolete) To dwell in a cave.
  "although perhaps / It may be heard at court that such as we / Cave here, hunt here, are outlaws, and in time / May make some stronger head"

intj

• (British, school slang) look out!; beware!
  "Ssh! Cave! Mum's the word! Not 'arf, or what?"