Information displayed to a user about someone else adding him or her to a contact list, a contact’s offline or online status, a missed conversation, voice mail message, service problem, or other item.
— Computer ScienceA communication generated by the occurrence of an event that a system or user asynchronously sends for receipt. A notification message is a communication that is intended to be read by a recipient.
— Computer ScienceA message or other indicator that informs users of events that are unrelated to their current activity, such as the number of new messages received while their computer is locked.
— Computer Science