what does sinkhole mean?

SINKHOLE as NOUN

Meaning
- a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof
Synonym(s)
- sink (what does sink mean?)
- swallow hole (what does swallow hole mean?)
Hypernyms(s) sinkhole is a kind of… Example: animal is a hypernym of mammal, plant is a hypernym of flower
- natural depression (what does natural depression mean?)
- depression (what does depression mean?)