Play a measure first (5)
I believe the answer is:
drama
'play' is the definition.
(I know that play can be written as drama)
'a measure first' is the wordplay.
'a measure' becomes 'D' (D is an example).
'first' becomes 'rama' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'd'+'rama'='DRAMA'
Can you help me to learn more?
(Other definitions for drama that I've seen before include "Play, emotional series of events" , "Stage production" , "Series of events involving conflicting forces" , "Acting" , "Turbulent emotional episode" .)