wool yarn made of long-staple fibres that have been combed to remove undesirable short fibres and make them lie parallel. In the spinning operation, which imparts the necessary twist to hold the fibres together, worsted yarns are more tightly twisted than are the bulkier woolen yarns.

Two yarns may be twisted together to form two-ply yarn, or three or four yarns may be twisted together to form three- or four-ply yarn. The soft, heavy yarn is strong and durable and is often used for sweaters.