blue hole
Noun
Meaning
blue hole (plural blue holes)
English Wikipedia has an article on:blue holeWikipedia
A submarine cave or sinkhole, a roughly circular, steep-walled depression that is typically anoxic below a certain depth.
Noun
blue hole (plural blue holes)
English Wikipedia has an article on:blue holeWikipedia
A submarine cave or sinkhole, a roughly circular, steep-walled depression that is typically anoxic below a certain depth.