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, Q. nigra.

Basket oak, Q. Michauxii.

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

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

Chestnut oak, Q. Prinus and Q. densiflora.

Chinquapin oak (see under Chinquapin), Q. prinoides.

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

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

Pin oak. Same as Swamp oak.

Post oak, Q. obtusifolia.

Red oak, Q. rubra.

Scarlet oak, Q. coccinea.

Scrub oak, Q. ilicifolia, Q. undulata, etc.

Shingle oak, Q. imbricaria.

Spanish oak, Q. falcata.

Swamp Spanish oak, or

Pin oak, Q. palustris.

Swamp white oak, Q. bicolor.

Water oak, Q. aguatica.

Water white oak, Q. lyrata.

Willow oak, Q. Phellos. Among the true oaks in Europe are:

Bitter oak, or

Turkey oak, Q. Cerris (see Cerris).

Cork oak, Q. Suber.

English white oak, Q. Robur.

Evergreen oak,

Holly oak, or

Holm oak, Q. Ilex.

Kermes oak, Q. coccifera.

Nutgall oak, Q. infectoria.

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

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

Australian, 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, the poison ivy. See under Poison.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Poison \Poi"son\, n. [F. poison, in Old French also, a potion, fr. L. potio a drink, draught, potion, a poisonous draught, fr. potare to drink. See Potable, and cf. Potion.]

1. Any agent which, when introduced into the animal organism, is capable of producing a morbid, noxious, or deadly effect upon it; as, morphine is a deadly poison; the poison of pestilential diseases.

2. That which taints or destroys moral purity or health; as, the poison of evil example; the poison of sin.

Poison ash. (Bot.)
   (a) A tree of the genus Amyris (A. balsamifera) found in the West Indies, from the trunk of which a black liquor distills, supposed to have poisonous qualities.
   (b) The poison sumac (Rhus venenata). [U. S.]

Poison dogwood (Bot.), poison sumac.

Poison fang (Zo["o]l.), one of the superior maxillary teeth of some species of serpents, which, besides having the cavity for the pulp, is either perforated or grooved by a longitudinal canal, at the lower end of which the duct of the poison gland terminates. See Illust. under Fang.

Poison gland (Biol.), a gland, in animals or plants, which secretes an acrid or venomous matter, that is conveyed along an organ capable of inflicting a wound.

Poison hemlock (Bot.), a poisonous umbelliferous plant (Conium maculatum). See Hemlock.

Poison ivy (Bot.), a poisonous climbing plant (Rhus Toxicodendron) of North America. It is common on stone walls and on the trunks of trees, and has trifoliate, rhombic-ovate, variously notched leaves. Many people are poisoned by it, if they touch the leaves. See Poison sumac. Called also poison oak, and mercury.

Poison nut. (Bot.)
   (a) Nux vomica.
   (b) The tree which yields this seed (Strychnos Nuxvomica). It is found on the Malabar and Coromandel coasts.

Poison oak (Bot.), the poison ivy; also, the more shrubby Rhus diversiloba of California and Oregon.

Poison sac. (Zo["o]l.) Same as Poison gland, above. See Illust. under Fang.

Poison sumac (Bot.), a poisonous shrub of the genus Rhus (R. venenata); -- also called poison ash, poison dogwood, and poison elder. It has pinnate leaves on graceful and slender common petioles, and usually grows in swampy places. Both this plant and the poison ivy (Rhus Toxicodendron) have clusters of smooth greenish white berries, while the red-fruited species of this genus are harmless. The tree (Rhus vernicifera) which yields the celebrated Japan lacquer is almost identical with the poison sumac, and is also very poisonous. The juice of the poison sumac also forms a lacquer similar to that of Japan.

Syn: Venom; virus; bane; pest; malignity.

Usage: Poison, Venom. Poison usually denotes something received into the system by the mouth, breath, etc. Venom is something discharged from animals and received by means of a wound, as by the bite or sting of serpents, scorpions, etc. Hence, venom specifically implies some malignity of nature or purpose.

Source: Webster's Revised Unabridged Dictionary (1913)