'Bur oak' definitions:

Definition of 'bur oak'

noun

Medium to large deciduous oak of central and eastern North America with ovoid acorns deeply immersed in large fringed cups; yields tough close-grained wood [syn: bur oak, burr oak, mossy-cup oak, mossycup oak, Quercus macrocarpa]

Definition of 'Bur oak'

From: GCIDE

Bur \Bur\, Burr \Burr\ (b[^u]r), 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; a seed vessel having hooks or prickles. Also, any weed which bears burs. [1913 Webster]
Amongst rude burs and thistles. --Milton. [1913 Webster]
Bur and brake and brier. --Tennyson. [1913 Webster]
2. The thin ridge left by a tool in cutting or shaping metal. See Burr, n., 2. [1913 Webster]
3. A ring of iron on a lance or spear. See Burr, n., 4. [1913 Webster]
4. The lobe of the ear. See Burr, n., 5. [1913 Webster]
5. The sweetbread. [1913 Webster]
6. A clinker; a partially vitrified brick. [1913 Webster]
7. (Mech.) (a) A small circular saw. (b) A triangular chisel. (c) A drill with a serrated head larger than the shank; -- especially a small drill bit used by dentists. [1913 Webster]
8. [Cf. Gael. borr, borra, a knob, bunch.] (Zool.) The round knob of an antler next to a deer's head. [Commonly written burr.] [1913 Webster]
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. [1913 Webster]