What is "bur oak"

Oak \Oak\ ([=o]k), n. [OE. oke, ok, ak, AS. [=a]c; akin to D. eik, G. eiche, OHG. eih, Icel. eik, Sw. ek, Dan. eeg.]

1. (Bot.) Any tree or shrub of the genus Quercus. The oaks have alternate leaves, often variously lobed, and staminate flowers in catkins. The fruit is a smooth nut, called an acorn, which is more or less inclosed in a scaly involucre called the cup or cupule. There are now recognized about three hundred species, of which nearly fifty occur in the United States, the rest in Europe, Asia, and the other parts of North America, a very few barely reaching the northern parts of South America and Africa. Many of the oaks form forest trees of grand proportions and live many centuries. The wood is usually hard and tough, and provided with conspicuous medullary rays, forming the silver grain.

2. The strong wood or timber of the oak.

   Note: Among the true oaks in America are:

   Barren oak, or

   Black-jack, Quercus nigra.

   Basket oak, Quercus Michauxii.

   Black oak, Quercus tinctoria; -- called also yellow oak or quercitron oak.

   Bur oak (see under Bur.), Quercus macrocarpa; -- called also over-cup or mossy-cup oak.

   Chestnut oak, Quercus Prinus and Quercus densiflora.

   Chinquapin oak (see under Chinquapin), Quercus prinoides.

   Coast live oak, Quercus agrifolia, of California; -- also called enceno.

   Live oak (see under Live), Quercus virens, the best of all for shipbuilding; also, Quercus Chrysolepis, of California.

   Pin oak. Same as Swamp oak.

   Post oak, Quercus obtusifolia.

   Red oak, Quercus rubra.

   Scarlet oak, Quercus coccinea.

   Scrub oak, Quercus ilicifolia, Quercus undulata, etc.

   Shingle oak, Quercus imbricaria.

   Spanish oak, Quercus falcata.

   Swamp Spanish oak, or

   Pin oak, Quercus palustris.

   Swamp white oak, Quercus bicolor.

   Water oak, Quercus aquatica.

   Water white oak, Quercus lyrata.

   Willow oak, Quercus Phellos. [1913 Webster] Among the true oaks in Europe are:

   Bitter oak, or

   Turkey oak, Quercus Cerris (see Cerris).

   Cork oak, Quercus Suber.

   English white oak, Quercus Robur.

   Evergreen oak,

   Holly oak, or

   Holm oak, Quercus Ilex.

   Kermes oak, Quercus coccifera.

   Nutgall oak, Quercus infectoria.

   Note: Among plants called oak, but not of the genus Quercus, are:

   African oak, a valuable timber tree ( Oldfieldia Africana).

   Australian oak or She oak, any tree of the genus Casuarina (see Casuarina).

   Indian oak, the teak tree (see Teak).

   Jerusalem oak. See under Jerusalem.

   New Zealand oak, a sapindaceous tree ( Alectryon excelsum).

   Poison oak, a shrub once not distinguished from poison ivy, but now restricted to Rhus toxicodendron or Rhus diversiloba.

   Silky oak or Silk-bark oak, an Australian tree ( Grevillea robusta).

   Green oak, oak wood colored green by the growth of the mycelium of certain fungi.

   Oak apple, a large, smooth, round gall produced on the leaves of the American red oak by a gallfly ( Cynips confluens). It is green and pulpy when young.

   Oak beauty (Zo["o]l.), a British geometrid moth ( Biston prodromaria) whose larva feeds on the oak.

   Oak gall, a gall found on the oak. See 2d Gall.

   Oak leather (Bot.), the mycelium of a fungus which forms leatherlike patches in the fissures of oak wood.

   Oak pruner. (Zo["o]l.) See Pruner, the insect.

   Oak spangle, a kind of gall produced on the oak by the insect Diplolepis lenticularis.

   Oak wart, a wartlike gall on the twigs of an oak.

   The Oaks, one of the three great annual English horse races (the Derby and St. Leger being the others). It was instituted in 1779 by the Earl of Derby, and so called from his estate.

   To sport one's oak, to be ``not at home to visitors,'' signified by closing the outer (oaken) door of one's rooms. [Cant, Eng. Univ.]

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.

   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.)

   1. A small circular saw.

   2. A triangular chisel.

   3. A drill with a serrated head larger than the shank; -- especially a small drill bit used by dentists.

8. [Cf. Gael. borr, borra, a knob, bunch.] (Zo["o]l.) 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.

alt. (taxlink Quercus macrocarpa species noshow=1). n. (taxlink Quercus macrocarpa species noshow=1).

n. 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: burr oak, mossy-cup oak, mossycup oak, Quercus macrocarpa]