bur

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A rough prickly husk or covering surrounding the seeds or fruits of plants such as the chestnut or the burdock.
2. n. A plant producing such husks or coverings.
3. n. A persistently clinging or nettlesome person or thing.
4. n. A rough protuberance, especially a burl on a tree.
5. n. Any of various rotary cutting tools designed to be attached to a drill.
6. n. Variant of burr².
7. n. Variant of burr³.

Century Dictionary and Cyclopedia

1. n. The rough, prickly case or covering of the seeds of certain plants, as of the chestnut and burdock.
2. n. Hence The plant burdock: as, “rude burs and thistles,”
3. n. In general, a protuberance upon, or a raised portion of, an object, usually more or less rough or irregular in form. Specifically— The lobe or lap of the ear. The circular boss round the root of an antler. Formerly, that part of a saddle-bow which protected the thighs and knees. It was often of steel, or plated with steel, and engraved or decorated with gilding. In engraving, slight ridges of metal raised upon a copper surface by the burin, the rocker, or the dry-point. It is sometimes wholly or partly removed by the scraper, but is often left to produce a peculiar effect of its own in the print. In mezzotint engraving, for example, the whole effect comes from the bur raised by the rocker, which is untouched in the deep shades and more or less burnished away to form the lights. In founding, the roughness left on portions of a casting, which is rubbed off on a stone. The rough neck left on a bullet in casting.
4. n. The name of various tools and appliances. A triangular chisel used to clear the corners of mortises. A small circular saw. A fluted reaming-tool. Same as bur-drill. A washer placed at the head of a rivet. A movable ring adjusted to the staff of a lance, and covered with minute projections to afford a grip to the gauntlet. It was grasped when the lance was laid in rest. See lance. A ring or plate attached to the handle of a battle-ax or mace to afford a good grip for either hand. Anything put under a wheel to stop its progress.
5. n. A partially vitrified brick; a clinker. Also called bur-brick.
6. n. The blank driven out of a piece of sheet-metal by a punch.
7. n. Waste raw silk.
8. n. A name for the club-moss, Lycopodium clavatum.
9. n. The sweetbread.
10. n. Same as burl, 2.
11. n. Same as burstone.
12. n. The rounded knob forming the base of a deer's horn.
13. n. The external meatus of the ear; the opening leading to the tympanum.
14. n. The guttural pronunciation of the rough r common in some of the northern counties of England, especially Northumberland; rhotacism.
15. n. A whirring noise. See birr, n.
16. To speak with a guttural or rough pronunciation of the letter r.
17. To talk or whisper hoarsely; murmur.
18. To make a whirring noise. See birr, verb
19. n. Same as burrow, 3.
20. n. A halo round the moon. Compare burrow, 4, brough, 4.
21. n. An abnormal outgrowth of wood, frequently of large size, occurring on the trunk or branch of a tree, usually as the result of some injury. See burl, 2.
22. To extract (burs and other extraneous matter) from (wool) by chemical or mechanical means.
23. To use a dental bur in the excavation of (a tooth-cavity).
24. n. The native Indian name for the banian-tree.

Wiktionary

1. n. A rough, prickly husk around the seeds or fruit of some plants.
2. n. Any of several plants having such husks.
3. n. A rotary cutting implement having a selection of variously shaped heads.

GNU Webster's 1913

1. n. (Bot.) Any rough or prickly envelope of the seeds of plants, whether a pericarp, a persistent calyx, or an involucre, as of the chestnut and burdock; a seed vessel having hooks or prickles. Also, any weed which bears burs.
2. n. The thin ridge left by a tool in cutting or shaping metal. See Burr, n., 2.
3. n. A ring of iron on a lance or spear. See Burr, n., 4.
4. n. The lobe of the ear. See Burr, n., 5.
5. n. The sweetbread.
6. n. A clinker; a partially vitrified brick.
7. n. A small circular saw.
8. n. A triangular chisel.
9. n. A drill with a serrated head larger than the shank; -- especially a small drill bit used by dentists.
10. n. (Zoöl.) The round knob of an antler next to a deer's head.

WordNet 3.0

1. n. seed vessel having hooks or prickles
2. v. remove the burrs from
3. n. small bit used in dentistry or surgery