A fringe is an ornamental appendage to the border of an item. It originally consisted of the ends of the warp, projecting beyond the woven fabric. More commonly it is made separate and sewed on, consisting sometimes of projecting ends, twisted or plaited together, and sometimes of loose threads of wool, silk, or linen, or narrow strips of leather, or the like.
A fringe is the front part of the hair that hangs down above the eyes - in American English this is usually called "bangs".
The Fringe is a term used to refer to non-mainstream theatre, where experimental forms of stagecraft are performed. The Edinburgh Festival is an arts festival held in Edinburgh, Scotland that has a large fringe theatre component.
By extension, any cultural manifestation not in the mainstream can be said to be on the fringe.