A fabric loom is set with rows of thread criss-crossing each other to form the fabric. Vertical (lengthwise) threads are attached to the loom itself. These are called the WARP threads. Next, threads are woven between the warp threads, usually at a 90˚angle. These fill in the fabric and are called WEFT threads. The variations in the way the Warp and Weft threads criss-cross each other are how different weaves of fabric are created.