One piece of music a month? (5)
I believe the answer is:
march
I believe this is a triple definition!
'one piece' is the first definition.
(I know that march is a type of musical composition)
'of' acts as a link.
'music' is the second definition.
(march is a kind of music)
'a month?' is the third definition.
(I know that March is a type of month)
(Other definitions for march that I've seen before include "Stride; month" , "Month, piece of music" , "Protest; month" , "The month for military movement" , "Walk smartly" .)