1. A hairstyle popularized by 1980's American girls to try and look like Madonna. It was usually combined with a stretch pants/skirt combination and jelly slippers.
2. Most recently popularized in the 2004 film, Napoleon Dynamite, where the title character's love interest wears a side-ponytail.
Check out the ponytail holder holding up my side-ponytail, its magenta, white and black, just like the laces on my LA Gears.