Slub (textiles)

A slub in textiles production refers to thickened areas of a fiber or yarn. Slubbed or slubby fabric is woven from slubby yarn (yarn with a very variable diameter). Both high and low slubbiness may be sought.

Slubs in spun fibers may be produced deliberately by varying spinning tension (see Novelty yarns#Slub). They are also produced when short, staple fibers are spun into a single yarn. Slubs may be valued or deliberately produced for aesthetic effect, but they may also be regarded as a defect caused by either uneven spinning or using low-grade, lumpy or short-staple fiber.