Country flag raised by a trio of dreamers (7)
I believe the answer is:
eritrea
'country' is the definition.
(I've seen this before)
'flag raised by a trio of dreamers' is the wordplay.
'flag' becomes 'tire' (I've seen this in other clues).
'raised by' shows that the letters should be reversed in order.
'a trio of dreamers' becomes 'rea' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tire' written backwards gives 'erit'.
'erit'+'rea'='ERITREA'
Can you help me to learn more?
(Other definitions for eritrea that I've seen before include "State of northeast Africa" , "nation" , "NE African state" , "It declared its independence from Ethiopia in 1993" , "Asmara area" .)