Couples do it on the floor (5)
I believe the answer is:
dance
'the floor' is the definition.
(dance floor is a kind of floor)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for dance that I've seen before include "Reel, say" , "Quickstep, e.g." , "Trip the light fantastic" , "Jig, say" , "Ball; hop" .)