A memorandum or memo's a document or other communication that aids the memory by recording events or observations on a topic, such as may be used in a business office. The plural form's either memoranda or memorandums. A memorandum may have any format, or it may have a format specific to an office or institution. In law specifically, a memorandum's a record of the terms of a transaction or contract, such as a policy memo, memorandum of understanding, memorandum of agreement, or memorandum of as… (More on Memorandum)