Singer in a trio? (6)
I believe the answer is:
treble
'singer' is the definition.
(I know that treble is a type of singer)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for treble that I've seen before include "Feat of winning three major trophies" , "Multiply by three - high-pitched" , "Multiple score in darts" , "Threefold - singing voice" , "Triple - soprano voice" .)