A spinning process where fibers are fed on to the end of the yarn while it is in the twisting zone that consists of a ring, a ring traveler, and a bobbin rotating at high speed. The traveler carries the yarn around the ring, making about 12 trips around the ring while 1 inch of yarn is taken up on the bobbin. The yarn produced is more uneven than open-end yarn, but it is stronger and smoother to touch because the fibers are more parallel.
Source: Tellason Denim Terminology