Dance floor — let it be firm! (8)
I believe the answer is:
flamenco
'dance' is the definition.
(I know that Flamenco is a type of dance)
'floor let it be firm' is the wordplay.
'floor' becomes 'fl' (I've seen this in other clues).
'let it be' becomes 'amen' ('amen' means 'let it be' or 'so be it').
'firm' becomes 'co' (a firm is a company).
'fl'+'amen'+'co'='FLAMENCO'
(Other definitions for flamenco that I've seen before include "Spanish music and dance" , "Spanish gypsy style of song and dance" , "Gypsy dance associated with Spain" , "Spanish gypsy music" , "Spanish guitar music" .)