Stalactite setting (4)
I believe the answer is:
cave
'stalactite setting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cave that I've seen before include "Hollow - warning" , "Troglodyte's home" , "Natural underground space" , "Subject of speleology" , "Natural hollow in side of hill or cliff" .)