(1) A value used to define the type of data sent for a distribution to a recipient. The message types supported on a system are defined when the mail server framework is configured. The value associated with the message type must be a unique type value.
(2) The logical structure of the data within a message. For example, the number and location of character strings.
(3) A number, up to 7 digits long, that identifies a message. SWIFT messages are identified by a 3-digit number; for example SWIFT message type MT S100.