Picasso-Braque movement (6)
I believe the answer is:
cubism
'picasso-braque movement' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cubism that I've seen before include "Artistic movement for which Picasso was famous" , "Art style of Picasso" , "Artistic movement in France beginning in early 20th century" , "Early twentieth century painting style" , "Art movement pioneered by Braque and Picasso before 1914" .)