Threading is an ancient method of hair removal originating in Central Asia and India. In threading, a thin (cotton or polyester) thread is doubled, then twisted. It is then rolled over the areas of unwanted hair, plucking the hair at the follicle level. Unlike tweezing, where single hairs are pulled out one at a time, threading can remove short lines of hair.
Advantages cited for threading as opposed to waxing are that it provides more precise control in shaping and is gentler on the skin.