(bûr)
1. A roughness or rough edge, especially one left on metal in casting or cutting.
2. A tool or device that raises a burr.
3. A dentist's drill with rough knothead: also burr drill.
4. A millstone made of burrstone: also spelled buhr.
5. The lobe of the ear.
6. A metal ring on the staff of a lance or handle of a battle-ax to keep the hand from slipping.
7. A halo around the moon or a star.
8. A blank punched out of a sheet of metal.
9. A washer to be slipped upon the end of a rivet before swaging, as in riveting leather.
10. A partly vitrified brick.
11. A hard lump of ore imbedded in a vein of softer material.
12. Bur¹.
—v.t.
1. To form a rough edge on.
2. To remove a rough edge from.
—v.i.
3. To operate a dentist's drill. Also spelled bur. ◆ Homophone: birr [Var. of BUR¹]

(bûr) noun
1. A rough guttural sound of r caused by the vibration of the uvula against the back part of the tongue: common in the north of England, but not to be confused with the Scottish trill.
2. Any rough, dialectal pronunciation: the Scottish burr.
3. A whirring sound; a buzz.
—v.t.
1. To pronounce with a rough or guttural articulation.
—v.i.
2. To speak with a burr.
3. To whir. Also spelled bur. ◆ Homophone: birr. [Imit.]

(bûr), Aaron,
1756–1836, American lawyer and statesman; vice president of the United States 1801–05.