Roaring years? (7)
I believe the answer is:
forties
'roaring years?' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.
This is all the clue.
Can you help me to learn more?
(Other definitions for forties that I've seen before include "The age" , "British shipping forecast area" , "See 25 Across" .)