A way of removing hair — usually from the face, and most often the eyebrows — using a thin cotton thread. The person doing it holds the thread twisted in a loop, often with one end held in their teeth, and rolls it across the skin so that the loop closes on the hairs and pulls them out at the root. It takes out a whole line of hairs at once, which is why it can shape an eyebrow into a clean line faster than pulling hair by hair with tweezers.

The method comes from South Asia and the Middle East, and it spread from there into salons all over the world. In English it is a normal, everyday salon word, not a technical one: you see it on price lists next to 'waxing', and people say 'I'm getting my eyebrows threaded' as easily as 'I'm getting a haircut'. Note the two forms — the noun is 'threading' (the service), and the verb is 'thread': they thread your eyebrows.

People usually say it hurts, but in a short sharp way, and many prefer it to waxing because nothing is put on the skin — no hot wax, no chemicals — so it suits sensitive skin. Threading is mainly for small, careful areas: eyebrows, upper lip, chin, the sides of the face. Nobody threads a whole leg.

Be ready for the other meanings of 'threading', because this is the rarer one. Most of the time 'threading' is just the -ing form of the ordinary verb 'thread' — threading a needle, threading your way through a crowd — and in computing 'threading' means running several parts of a program at the same time.