Reminder (4)
'reminder' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for memo that I've seen before include "Office note" , "diplomatic communication?" , "In brief, a note of events" , "- Currie, Br. politician" , "Brief note, usually between co-workers" .)
(Other definitions for prod that I've seen before include "Urge or stimulate" , "Induce action (with stick etc?)" , "Poke, jab, nudge" , "Give a reminder" , "Motivate; jab" .)
(Other definitions for asa that I've seen before include "OT character" , "iconoclastic king of Judah ..." .)
'reminder' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for aide-memoire that I've seen before include "A help for recollection" , "Reminder" .)