One taking turns as an opener? (3)
I believe the answer is:
key
'an opener?' is the definition.
(keys open things)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for key that I've seen before include "Typewriter button, isle" , "Clue" , "Lock-opener" , "Piano lever" , "Device for lock" .)