Song about People's Republic (7)
I believe the answer is:
armenia
'republic' is the definition.
(I've seen this before)
'song about people's' is the wordplay.
'song' becomes 'aria' (piece of music in an opera).
'about' means one lot of letters goes inside another.
'people' becomes 'men' (men are people).
'aria' going around 'men' is 'ARMENIA'.
(Other definitions for armenia that I've seen before include "Republic in N W Asia" , "Caucasian republic" , "Former Russian republic, its capital Yerevan" , "Republic, formerly part of the Soviet Union" , "Country in the Caucasus, capital Yerevan" .)