Note, missive (7)
I believe the answer is:
message
This clue is a double definition.
'note' is the first definition.
(a note is a short message)
'missive' is the second definition.
(I've seen this before)
(Other definitions for message that I've seen before include "Tidings" , "Communication that is sent" , "meaning" , "Spoken or written communication" , "Missive" .)