reminder; note for future reference
Formal or literary term for a written note or record kept to aid memory. Often appears in compounds like 備忘録 (memorandum book).
I wrote down the meeting details as a reminder.
I'll leave this note for future reference.
memorandum; notebook; commonplace book
residual value; scrap value; memorandum value
Compound of 備 (prepare, equip) and 忘 (forget), literally 'prepare against forgetting'. The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning of a reminder or note.