cave

Etymology 1

From Middle English cave, borrowed from Old French cave, from Latin cava (“cavity”), from cavus (“hollow”). Cognate with Tocharian B kor (“throat”), Albanian cup (“odd, uneven”), Ancient Greek κύαρ (kúar, “eye of needle, earhole”), Old Armenian սոր (sor, “hole”), Sanskrit शून्य (śūnya, “empty, barren, zero”). Displaced native Old English sċræf. More at cavum, cavus and cage.

noun

1. A large, naturally-occurring cavity formed underground or in the face of a cliff or a hillside.
   We found a cave on the mountainside where we could take shelter.
2. A hole, depression, or gap in earth or rock, whether natural or man-made.
   Every boy at one time or another has dug a cave; I suppose because ages and ages ago his ancestors had to live in caves, […] 1918, Edward Alfred Steiner, Uncle Joe's Lincoln, page 52
3. A storage cellar, especially for wine or cheese.
   This wine has been aged in our cave for thirty years.
4. A place of retreat, such as a man cave.
   My room was a cozy cave where I could escape from my family.
5. (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.
6. (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) […] 1986, National Council on Radiation Protection and Measurements, Radiation Alarms and Access Control Systems, page 45
7. (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. 1951, James Deans Cumming, Diamond Drill Handbook, page 134
8. (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. 1885, Angelo Heilprin, Town Geology: The Lesson of the Philadelphia Rocks, page 79
9. (figurative, also slang) The vagina.
   Then without a word she lay on her back in the bed, her dark blond pubic hair rising about her dark wet cave like dried brush about a hidden spring. 1976, Chester Himes, My Life of Absurdity, page 59
10. (slang, politics, often "Cave") A group that breaks from a larger political party or faction on a particular issue.
    Without joining the cave, Hyde had abstained both in December 1956 and May 1957. 1964, Leon D. Epstein, British Politics in the Suez Crisis, page 125
11. (obsolete) Any hollow place, or part; a cavity.
12. (programming) A code cave.
    Once a code cave is created, you can execute it using either thread injection or thread hijacking. […] Additionally, you'd need to make sure that the cave properly cleans the stack. 2016, Nick Cano, Game Hacking: Developing Autonomous Bots for Online Games

verb

1. To surrender.
   He caved under pressure.
2. To collapse.
   First the braces buckled, then the roof began to cave, then we ran.
3. To hollow out or undermine.
   The levee has been severely caved by the river current.
4. To engage in the recreational exploration of caves.
   I have caved from Yugoslavia to Kentucky.
   Let's go caving this weekend.
   Pam has been caving for 25 years. She and her husband Tim are among the top cavers in the country. They are passionate about the world hidden beneath our feet and they were to be my instructors and guides on my first ever foray below ground that didn't involve getting on the tube. 2007-09-29, Kate Humble, “What lies beneath”, in The Guardian
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.
   The deposit is caved by knocking out the posts.
6. (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. 1999, Andy Wood, The Politics of Social Conflict: The Peak Country, 1520-1770, page 319
7. (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 a. 1611, William Shakespeare, Cymbeline, act 4, scene 2

Etymology 2

Borrowed from Latin cavē, second-person singular present active imperative of caveō (“to beware”). Used at Eton College, Berkshire.

intj

1. (Britain, school slang) look out!; beware!
   Ssh! Cave! Mum's the word! Not 'arf, or what? 1989, Ben Elton, Richard Curtis, Private Plane (Blackadder Goes Forth), season 4, episode 4, spoken by Lt. George (Hugh Laurie)