Ōak, n.

. (ōk), n. [A.-S. ác, ácbeám, áctreow, D. eik, eik-boom, L. Ger. eeke, Icel. eik, eyk, Sw. ek, elträd, Dan. eeg, eegetræ, O. H. Ger. eih, M. H. Ger. eich, N. H. Ger. eiche, eichbaum.] (Bot.) A tree of the genus Quercus, of which there are many species. They are trees or shrubs, having lobed or notched alternate leaves, and the nut, or acorn, is more or less inclosed in a scaly involucre, called the cupule. The flowers are green or yellow catkins. All the species are found in the northern hemisphere, though some are tropical. The white oak of the United States is Q. alba, and is a large tree, well known for the value of its timber. The live oak is Q. virens, and is very highly prized for ship-building.