Key above Caps Lock (3)
I believe the answer is:
tab
'key above caps lock' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tab that I've seen before include "Flap; meal bill" , "Text indent key" , "Flap; illicit drug pill (slang)" , "Small flap - bill" , "Tally of orders in bar" .)