sig

noun4

1. •
   (Internet, informal) a signature at the end of an email or online message, usually a few short lines that give the writer's name and other details

   • Your sig should ideally be four or five lines long, six or seven at the maximum. Since it will be repeated on hundreds of messages, a long signature wastes bandwidth and is therefore rude. — 1995
2. •
   a short form of "Sigma" used in the names of student fraternities and sororities, where it stands for the Greek letter

   • Here are 6 of the most cartoonishly sexist, aggressive, and straight-up nuts fraternity and sorority email chains ever released to the public. Let them be a warning to young Kappa Sigs everywhere. — 2014
3. •
   (slang, humorous) Short for sigma in phrases like "what the sigma"

   • What the sig is this?
4. •
   (dialect, old-fashioned) the liquid waste that people and animals release from the body, urine

verb1

1. •
   (slang) To good-naturedly make fun of someone; to signify.

   • And it is a matter of pride. No Black person wants to be "sigged" about or capped all over. — 1969

noun1

1. •
   Initialism of special interest group.