Session Initiated Protocol or SIP. A standard communications protocol that establishes, modifies, and terminates real-time multimedia communications sessions transmitted over the internet. These communications generally include Voice over Internet Protocol (VoIP) calls, video conferencing, and online gaming. For VoIP calls, SIP uses other protocols, including Real-time Transport Protocol (RTP) and Secure Real-time Transport Protocol (SRTP).
Merriam-Webster Online Dictionary
sip (verb)intransitive verb
transitive verb
to take a sip of something especially repeatedly
1.
to drink in small quantities
2.
to take sips from
1.
a small draft taken with the lips
2.
the act of sipping