Covered entrance concealed by top orchestra (5)
I believe the answer is:
porch
'covered entrance' is the definition.
(I've seen this before)
'concealed by top orchestra' is the wordplay.
'concealed by' says the answer is hidden in the clue.
'PORCH' can be found hidden inside 'top orchestra'.
(Other definitions for porch that I've seen before include "Roofed entrance to house" , "Protection over a doorway" , "architectural feature" , "Covered entrance to a building" , "Covered entrance to house" .)