Part of the choir is heard in Eire (5)
I believe the answer is:
irish
'in eire' is the definition.
(I know that Irish located in the administrative territorial entity Republic of Ireland)
'part of the choir is heard' is the wordplay.
'part of' indicates a hidden word.
'IRISH' is hidden in the letters of 'choir is heard'.
(Other definitions for irish that I've seen before include "Native to the Emerald Isle" , "Passion" , "Eg, native to Dublin" , "said to be lucky" , "W European" .)