Message (4)
'message' is the definition.
(memo is a kind of message)
This is all the clue.
(Other definitions for memo that I've seen before include "diplomatic communication?" , "Note written as a reminder" , "- Currie, Br. politician" , "Office note" , "It will remind" .)
'message' is the definition.
(I've seen this before)
This is the entire clue.
(Another definition for communication that I've seen is " Message; type of cord".)