caving

As a recreational activity, this term is the standard name for the sport of spelunking. While "spelunking" is common in North American English, "caving" is the preferred term globally and among professional enthusiasts, as it is perceived as more technical and serious.

When used to describe structural failure, the word carries a heavy connotation of danger and instability. It specifically refers to a vertical or inward collapse, distinguishing it from a general "crumbling" or "breaking" of a structure.