Singer whose heart is in English opera (5)
I believe the answer is:
tenor
'singer' is the definition.
(tenor is a kind of singer)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for tenor that I've seen before include "Voice of Tamino" , "Carreras, for example" , "One singing" , "Eg, Luciano Pavarotti" , "Male singing voice of high pitch" .)