Ikat a technique of tie-dyeing and weaving where the yarn is tie-dyed (at pre-determined intervals) such that the final pattern emerges once the fabric is woven. Every woven fabric has a warp (the length) and a weft (the width). Yarn is set on the loom in the warp, and a weaver passes a shuttle with yarn through the width of the fabric to weave the weft into the warp. This is the case for any handwoven fabric, but in ikat the yarn itself contains the pattern because it has been tie-dyed in a particular design before the weaving begins.
See our slideshow on the ikat making process: http://on.fb.me/LPZKLZ
Within the craft of ikat, you have warp ikat (where only the warp yarns are tie-dyed), weft ikat (only the weft yarns are tie-dyed), and double ikat (where both the warp and weft yarns are tie-dyed). Double ikat requires a lot of skill and precision because the yarn has to be dyed in such a way that the weft and warp patterns intersect while weaving to create a stronger colour and a bolder design.
In India ikat is found in Andhra Pradesh and Orissa. Andhra ikat motifs are generally more geometric, while Orissa ikat motifs often depict the flora and fauna of Orissa.