burl

Short definition from Wiktionary

Noun

1. 1
   A tree growth in which the grain has grown in a deformed manner; a burr knot.
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.

Proper noun

1. 1
   A surname.