memorandum

noun

1. A short note serving as a reminder.

   “....be more difficult or uncertain than it had been for so many weeks, I had scarcely for a moment adverted to it as necessary, or placed it amongst my memoranda against this parting interview; and my final anxieties being spent in comforting her with hopes, and in pressing upon her the necessity of getting some medicines for a violent cough and hoarseness with which she was troubled, I wholly forgot it until it was too late to recall her.”

2. A written business communication.

   “The Trump administration will allow federal workers to promote their religious beliefs to colleagues, display religious items at work and pray together or individually, according to a memorandum issued Monday by the Office of Personnel Management.”

3. A brief diplomatic communication.
4. A page in an annual publication honoring the memory of a person who died during the past year.