A facility for exchanging messages in real-time with other people over the Internet and tracking the progress of a given conversation.
Source(s):
NIST SP 800-101 Rev. 1
a facility for exchanging messages in real-time with other people over the Internet and tracking the progress of the conversation.
Source(s):
NISTIR 7250
under Instant Messaging
NISTIR 7387
under Instant Messaging