Word | Noun | Adjective | Verb | Adverb |
---|---|---|---|---|
natural depression | Yes | No | No | No |
swallow hole | Yes | No | No | No |
natural depression (noun) | swallow hole (noun) |
---|---|
a sunken or depressed geological formation | a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof |