: an occurrence in which something (such as the roof or walls of a building or cave) suddenly falls down or inward
What made you want to look up cave-in? Please tell us where you read or heard it (including the quote, if possible).
Take Our 10-Question Quiz
The commonly misspelled words quiz
How strong is your vocabulary?
The Vocab Quiz Game for iPhone & iPad
"Incredibly fun and addictive. And informative!" User Review, iTunes