A memorandum (abbrev.: memo; from Latin memorandum est, "It must be remembered (that)...") is a note, document or other communication that helps the memory by recording events or observations on a topic, such as may be used in a business office. The plural form of the Latin noun memorandum so derived is properly memoranda, but if the word is deemed to have become a word of the English language, the plural memorandums, abbreviated to memos, may be used. (See also Agenda, Corrigenda, Addenda).
A memorandum can have only a certain number of formats; it may have a format specific to an office or institution. In law specifically, a memorandum is a record of the terms of a transaction or contract, such as a policy memo, memorandum of understanding, memorandum of agreement, or memorandum of association. Alternative formats include memos, briefing notes, reports, letters or binders. They could be one page long or many. They may be considered as grey literature. If the user is a cabinet minister or a senior executive, the format might be rigidly defined and limited to one or two pages. If the user is a colleague, the format is usually much more flexible. At its most basic level, a memorandum can be a handwritten note to one's supervisor. In business, a memo is typically used by firms for internal communication, as opposed to letters which are typically for external communication. Hence, we can consider memoranda as an upward communication process through which any complaint, issues, opinion, views and suggestion are put forward to the authorized level.
A specific type of memorandum is the policy briefing note (alternatively referred to in various jurisdictions and governing traditions as policy issues paper, policy memoranda, or cabinet submission amongst other terms), a document for transmitting policy analysis into the political decision making sphere. Typically, a briefing note may be denoted as either “for information” or “for decision”.