Part 870

Buoy"an*cy (&?;), n.; pl. Buoyancies (&?;). 1. The property of floating on the surface of a liquid, or in a fluid, as in the atmosphere; specific lightness, which is inversely as the weight compared with that of an equal volume of water.

2. (Physics) The upward pressure exerted upon a floating body by a fluid, which is equal to the weight of the body; hence, also, the weight of a floating body, as measured by the volume of fluid displaced.

Such are buoyancies or displacements of the different classes of her majesty's ships. Eng. Cyc.

3. Cheerfulness; vivacity; liveliness; sprightliness; -- the opposite of heaviness; as, buoyancy of spirits.

Buoy"ant (&?;), a. [From Buoy, v. t. & i.] 1. Having the quality of rising or floating in a fluid; tending to rise or float; as, iron is buoyant in mercury. "Buoyant on the flood." Pope.

2. Bearing up, as a fluid; sustaining another body by being specifically heavier.

The water under me was buoyant. Dryden.

3. Light-hearted; vivacious; cheerful; as, a buoyant disposition; buoyant spirits. -- Buoy"ant*ly, adv.

Bu*pres"ti*dan (&?;), n. [L. buprestis, Gr. &?;, a poisonous beetle, which, being eaten by cattle in the grass, caused them to swell up and and die; &?; ox, cow + &?; to blow up, swell out.] (Zoöl.) One of a tribe of beetles, of the genus Buprestis and allied genera, usually with brilliant metallic colors. The larvæ are usually borers in timber, or beneath bark, and are often very destructive to trees.

{ Bur, Burr } (&?;), n. [OE. burre burdock; cf. Dan. borre, OSw. borra, burdock, thistle; perh. akin to E. bristle (burr- for burz-), or perh. to F. bourre hair, wool, stuff; also, according to Cotgrave, "the downe, or hairie coat, wherewith divers herbes, fruits, and flowers, are covered," fr. L. burrae trifles, LL. reburrus rough.] 1. (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. Also, any weed which bears burs.

Amongst rude burs and thistles. Milton.

Bur and brake and brier. Tennyson.

2. The thin ridge left by a tool in cutting or shaping metal. See Burr, n., 2.

3. A ring of iron on a lance or spear. See Burr, n., 4.

4. The lobe of the ear. See Burr, n., 5.

5. The sweetbread.

6. A clinker; a partially vitrified brick.

7. (Mech.) (a) A small circular saw. (b) A triangular chisel. (c) A drill with a serrated head larger than the shank; -- used by dentists.

8. [Cf. Gael. borr, borra, a knob, bunch.] (Zoöl.) The round knob of an antler next to a deer's head. [Commonly written burr.]

Bur oak (Bot.), a useful and ornamental species of oak (Quercus macrocarpa) with ovoid acorns inclosed in deep cups imbricated with pointed scales. It grows in the Middle and Western United States, and its wood is tough, close-grained, and durable. -- Bur reed (Bot.), a plant of the genus Sparganium, having long ribbonlike leaves.

Bur"bolt` (&?;), n. A birdbolt. [Obs.] Ford.

Bur"bot (&?;), n. [F. barbote, fr. barbe beard. See 1st Barb.] (Zoöl.) A fresh- water fish of the genus Lota, having on the nose two very small barbels, and a larger one on the chin. [Written also burbolt.]

The fish is also called an eelpout or ling, and is allied to the codfish. The Lota vulgaris is a common European species. An American species (L. maculosa) is found in New England, the Great Lakes, and farther north.

Bur`de*lais" (&?;), n. [F. bourdelais, prob. fr. bordelais. See Bordelais.] A sort of grape. Jonson.

Bur"den (bû"d'n), n. [Written also burthen.] [OE. burden, burthen, birthen, birden, AS. byrðen; akin to Icel. byrði, Dan. byrde, Sw. börda, G. bürde, OHG. burdi, Goth. baúrþei, fr. the root of E. bear, AS. beran, Goth. bairan. √92. See 1st Bear.] 1. That which is borne or carried; a load.

Plants with goodly burden bowing. Shak.

2. That which is borne with labor or difficulty; that which is grievous, wearisome, or oppressive.

Deaf, giddy, helpless, left alone, To all my friends a burden grown. Swift.