memorandum

A short note written as a reminder.

A written record or communication, as in a business office. synonym: letter.

A short document outlining the terms of an agreement, especially as a draft leading to a formal, detailed contract.

A writing submitted to a court by a party arguing an aspect of a case; a brief.

A decision of an appellate court, particularly one that is not accompanied by any detailed explanation of the basis for the decision.