Definitions of burl:

• noun:   a large rounded outgrowth on the trunk or branch of a tree
• noun:   the wood cut from a tree burl or outgrowth; often used decoratively in veneer
• noun:   soft lump or unevenness in a yarn; either an imperfection or created by design
• verb:   remove the burls from cloth
• name:  A male given name (rare: 1 in 20000 males; popularity rank in the U.S.: #996)
• name:  A surname (very rare: popularity rank in the U.S.: #38466)