Muse count (4)
I believe the answer is:
nine
'muse count' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nine that I've seen before include "Number of the ancient Muses" , "A number of worthies" , "Days Lady Jane 5 ac reigned" , "One over the eight" , "One more than fourteen across" .)