Warps are the parallel strings stretched from loom beam to loom beam upon which rows of knots are tied. Most weavers use cotton for warp material if it is available because it is easier to weave a flat, straight rug on cotton warps than on wool warps (wool yarn is more elastic than cotton string, and is more affected by changes in humidity). Weavers who are semi-nomadic pastoralists (i.e. not farmers) are much more likely to use wool than cotton for warp and weft.
Wefts run across the width of the rug, over and under the warp strings and between rows of knots. Most often wefts are made of cotton, wool, or silk . Wefts help hold rows of knots in place and strengthen the structure of the rug.
Fringes are formed by gathering and knotting together bundles of warp strings at both ends of the rug after the rug has been cut from the loom. The knots in these bundles of warp strings keep pile knots and end finishes tight at the rug's ends.