back ‧ drop /ˈbækdrɒp $ -drɑːp/ BrE AmE noun [countable]
1 . literary the ↑ scenery behind something that you are looking at
backdrop to
The sea made a splendid backdrop to the garden.
2 . the conditions or situation in which something happens
against a backdrop of something
a love story set against a backdrop of war and despair
3 . a painted cloth hung across the back of a stage