That fucking annoying lady that never stops talking. Usually a friend of your mom's.
``Mom'', I said, ``If you ever turn into that kind of yenta, I will have to kill you.''
Originally a packet used in TCP/IP to establish a connection, it is now commonly used as an "Are you there?" request to another user on a talker. It is also used in the less common form "SYN SYN ENQ" - two SYNchronization bytes, then an ENQuiry. The latter form is pretty much the same as the former.