Let men test broadcast in colony (10)
I believe the answer is:
settlement
'colony' is the definition.
(synonyms)
'let men test broadcast' is the wordplay.
'broadcast' is an anagram indicator.
'let'+'men'+'test'='letmentest'
'letmentest' with letters rearranged gives 'SETTLEMENT'.
'in' acts as a link.
(Other definitions for settlement that I've seen before include "Reservation" , "local community" , "ruling" , "deal" , "Resolution" .)