Girl blowing a million in the States (5)
I believe the answer is:
erica
'million in the states' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'girl blowing a' is the wordplay.
'girl blowing' becomes 'eric' (I can't explain this - if you can you should give a lot more credence to this answer).
'eric'+'a'='ERICA'
(Other definitions for erica that I've seen before include "growing up on the moors" , "Shrubs" , "Girl - heather" , "Woman" , "Heath genus; girl's name" .)