slub

A small thickened portion or knot found in yarn, caused by defects or intentionally leaving sections of the yarn unspun.

The challenge is not just to produce a thick-and-thin yarn, but to make soft slubs, connected by nicely spun yarn without overtwist. The should not be lumps and bumps that happen by accident, but a contrived texture, with the size and placement of the slubs completely controlled by the spinner.

The huge bolts of cloth had to be checked for imperfections such as slubs and misweaves.

Fabric fiber produced by slubbing.

To draw and twist fibers in order to prepare them for spinning.