From the acronym S.E.G. (shit eating grin). Used as an all-encompassing name for jocks, frat boys, bros, douche bags, ect., and refers to the cheesy smile the aforementioned often display, usually before date-rape, or climbing into a raised truck. Coined in Southern California in 2006.
Acronym for Sexually Educated Girl. The type of girl that has received a significantsexual education so that she avoid's all measures to avoid getting pregnant or catching an STD.
Dude 1: So shall we do it,
SEG: Yes, Do you have a condom? First I need to see the expiry date on your condom. Is it a Trojan or Durex, or Store brand? Where have you stored you condom, in dry warm conditions? Do you have lube? Is it water based or oil based? I think just to be sure, I better give you a blowjob with two condoms on.
Short for segment, segamatron, seggie, segmeena and segatron (a variation on segamatron), a Seg is a creature of very small stature, likened to a hobbit, of JRR Tolkien fame. They feed on blackcurrant cordial and baked potatoes, and move around in a shuffling manner. They are extremely rare and have often had other animals, such as kia, the wife of the famous willow mistaken for them.