knoop

  1. button
  2. (in touw, kabel) knot
  3. [MATH.] node
  4. [PHYS.] (rustpunt) oscillation node
  5. [TEX.] slub, nub, nep

Nubs & Slubs

Linen, hemp & wool are two yarns which are well-known for having little nubs and slubs along the length of the yarn.

Slubs occur when a yarn does not have a consistent diameter along the whole length of the thread. Where the yarn is thicker it interacts with the warp yarns differently causing visible slubs.

Nubs may appear as little lumps in the fabric or sometimes as little loops. These loops may look like pulls but they are actually a natural part of the yarn structure. They differ from a pull in that they are thin and a little wispy, and do not affect the fabric around them – i.e. there is no tension in the area around them. These can be left as they will not affect the integrity of the sling. Slubs and nubs will be more noticeable if there is a high contrast between weft and warp, or if the linen yarn is especially thick.

https://www.oschaslings.com/blog/fabric-characteristics/