crewel

This term is highly specialized and primarily used within the context of textile arts and historical embroidery. It refers specifically to a two-ply wool yarn that is twisted in a way that allows it to lie flat on the fabric, making it distinct from standard knitting wool or crochet yarn.

In modern usage, the word often appears as part of the compound "crewel work," which describes the specific technique of surface embroidery using this yarn. While it functions as both a noun and an adjective, it is rarely used outside of craft circles or museum descriptions of antique textiles.