1.  oak(n = noun.plant) Array - the hard durable wood of any oak; used especially for furniture and flooring; Array
is a kind of wood
has particulars: fumed oak, holm oak

2.  oak(n = noun.plant) oak tree - a deciduous tree of the genus Quercus; has acorns and lobed leaves; "great oaks grow from little acorns"
is a kind of tree
has parts: acorn
is a member of genus quercus, quercus
has particulars: live oak, white oak, european turkey oak, quercus cerris, turkey oak, quercus coccinea, scarlet oak, jack oak, northern pin oak, quercus ellipsoidalis, red oak, evergreen oak, holly-leaved oak, holm oak, holm tree, quercus ilex, laurel oak, quercus imbricaria, shingle oak, bluejack oak, quercus incana, turkey oak, california black oak, quercus kelloggii, american turkey oak, quercus laevis, turkey oak, laurel oak, pin oak, quercus laurifolia, overcup oak, quercus lyrata, scrub oak, japanese oak, quercus grosseserrata, quercus mongolica, chestnut oak, possum oak, quercus nigra, water oak, nuttall's oak, nuttall oak, quercus nuttalli, pin oak, quercus palustris, swamp oak, quercus phellos, willow oak, box white oak, brash oak, iron oak, post oak, quercus stellata, cork oak, quercus suber, quercus texana, spanish oak, chinese cork oak, quercus variabilis, black oak, quercitron, quercitron oak, quercus velutina, yellow oak

1.  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. [1913 Webster]

2.  The strong wood or timber of the oak. [1913 Webster]
" 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)." [1913 Webster]

oak, n.
1 any tree or shrub of the genus Quercus usu. having lobed leaves and bearing acorns.
2 the durable wood of this tree, used esp. for furniture and in building.
3 (attrib.) made of oak (oak table).
4 a heavy outer door of a set of university college rooms.
5 (the Oaks) (treated as sing.) an annual race at Epsom for three-year-old fillies (from the name of a nearby estate).

Idiom:
oak-apple (or -gall) an apple-like gall containing larvae of certain wasps, found on oak trees.

Derivative:
oaken adj.

Etymology:
OE ac f. Gmc

N  strength, power, energy, vigor, force, main force, physical force, brute force, spring, elasticity, tone, tension, tonicity, stoutness, lustihood, stamina, nerve, muscle, sinew, thews and sinews, physique, pith, pithiness, virtility, vitality, athletics, athleticism, gymnastics, feats of strength, adamant, steel, iron, oak, heart of oak, iron grip, grit, bone, athlete, gymnast, acrobat, superman, Atlas, Hercules, Antaeus, Samson, Cyclops, Goliath, tower of strength, giant refreshed, strengthening, invigoration, refreshment, refocillation, dynamics, statics, strong, mighty, vigorous, forcible, hard, adamantine, stout, robust, sturdy, hardy, powerful, potent, puissant, valid, resistless, irresistible, invincible, proof against, impregnable, unconquerable, indomitable, dominating, inextinguishable, unquenchable, incontestable, more than a match for, overpowering, overwhelming, all powerful, all sufficient, sovereign, able-bodied, athletic, Herculean, Cyclopean, Atlantean, muscular, brawny, wiry, well-knit, broad-shouldered, sinewy, strapping, stalwart, gigantic, manly, man-like, manful, masculine, male, virile, unweakened, unallayed, unwithered, unshaken, unworn, unexhausted, in full force, in full swing, in the plenitude of power, stubborn, thick-ribbed, made of iron, deep-rooted, strong as a lion, strong as a horse, strong as an ox, strong as brandy, sound as a roach, in fine feather, in high feather, built like a brick shithouse, like a giant refreshed, strongly, by force, by main force, our withers are unwrung, Blut und Eisen, coelitus mihi vires, du fort au diable, en habiles gens, ex vi termini, flecti non frangi, he that wrestles with us strengthens our nerves an, inflexible in faith invincible in arms.

american turkey oak, american white oak, arizona white oak, basket oak, bear oak, black oak, blackjack oak, bluejack oak, box white oak, brash oak, brown oak, bur oak, burr oak, california black oak, california live oak, california white oak, canyon live oak, canyon oak, chestnut oak, chinese cork oak, chinkapin oak, chinquapin oak, coast live oak, common oak, cork oak, cow oak, dwarf chinkapin oak, dwarf chinquapin oak, dwarf oak, eastern poison oak, english oak, european turkey oak, evergreen oak, fumed oak, garry oak, golden oak mushroom, holly-leaved oak, holm oak, huckleberry oak, interior live oak, iron oak, jack oak, japanese oak, jerusalem oak, laurel oak, live oak, maul oak, mossy-cup oak, mossycup oak, mountain oak, myrtle oak, northern oak fern, northern pin oak, northern red oak, nuttall oak, nuttall's oak, oak apple, oak blight, oak chestnut, oak fern, oak leaf, oak leaf cluster, oak tree, oregon oak, oregon white oak, overcup oak, pedunculate oak, pin oak, poison oak, possum oak, post oak, quercitron oak, red oak, red-flowered silky oak, scarlet oak, scrub oak, seaside scrub oak, shingle oak, shumard oak, shumard red oak, silk oak, silky oak, silver oak, southern live oak, southern red oak, spanish oak, swamp chestnut oak, swamp oak, swamp red oak, swamp white oak, tanbark oak, turkey oak, valley oak, valley white oak, water oak, western poison oak, white oak, willow oak, yellow chestnut oak, yellow oak