One taking piano course? (6)
I believe the answer is:
player
'one taking' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'piano course?' is the wordplay.
'piano' becomes 'p'.
'course?' becomes 'layer' (course is a kind of layer).
'p'+'layer'='PLAYER'
Can you help me to learn more?
(Other definitions for player that I've seen before include "South African golfer, b. 1935" , "Actor - footballer?" , "Gamer or sportsman" , "Sportsperson; actor" , "Contestant" .)