burls

/B ER1 L Z/
noun
  1. 1

    A tree growth in which the grain has grown in a deformed manner.

  2. 2

    Wood of a mottled veneer, usually cut from such a growth.

  3. 3

    A knot or lump in thread or cloth.

verb
  1. 1

    To remove the knots in cloth.

Source: https://en.wiktionary.org/wiki/burl, https://en.wiktionary.org/wiki/burls