Note means "not at home" (4)
I believe the answer is:
away
'not at home' is the definition.
(I've seen this before)
'note means' is the wordplay.
'note' becomes 'a' (musical note).
'means' becomes 'way' (a way or means of doing something).
'a'+'way'='AWAY'
(Other definitions for away that I've seen before include "Away in the distance" , "Detached" , "On holiday" , "Not present, having left" , "Location of match played on opponent's ground" .)