Harvest season (6)
I believe the answer is:
autumn
'harvest season' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for autumn that I've seen before include "Season, has its music too (Keats)" , "October's season" , "1 Season of mists and mellow fruitfulness" , "Fall (over the pond?)" , "One of the seasons" .)