Time to muse (5)
I believe the answer is:
erato
'muse' is the definition.
(I know that Erato is a muse)
'time to' is the wordplay.
'time' becomes 'era' (era is a kind of time).
'era'+'to'='ERATO'
(Other definitions for erato that I've seen before include "Muse of lyric love-poetry" , "inspiration for poetry" , "Poet's inspiration" , "Source of artistic inspiration" , "Lyric poetry's muse" .)