Fashion magazine since 1945 (4)
I believe the answer is:
elle
'fashion magazine since 1945' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for elle that I've seen before include "Is she in France" , "World's best-selling fashion magazine" , "Fashion magazine - the French "She"" , "French word for 'she'" , "Ms MacPherson, supermodel" .)