The word ‘Kilim‘ is of Turkish origin and basically refers to a pileless textile. The pile is simply the rug term to describe the surface of the rug, and how dense it is.
The main difference between a Kilim rug and other types of handmade rugs is that a Kilim is a flatweave. What is a flatweave? Flatweave describes a rug that is woven on a loom rather than knotted (by hand one knot at a time). It is created by interlocking warp (vertical) and weft (horizontal) threads. So still very much made by hand - but with a weaving technique, rather than a knotting. You can read a more in depth guide to Kilim rugs here.