Radio City Music Hall style (3,4)
I believe the answer is:
art deco
'radio city music hall style' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for art deco that I've seen before include "Architecture and design movement of the 1920s and 30s" , "Highly geometric style" , "Visual design style - redcoat (anag)" , "1920s and 30s style of art and architecture" , "1920s and 1930s ornamental style" .)