Oak
any species of the genus Quercus and specifically Q. robur, the common British oak. It is sometimes 60 to 100 feet high, with a girth of 70 feet. There are two varieties-sessiliflora, with sessile, and pedunculata, with pedunculated flowers; the latter is the most common in natural woods. Its timber is whitish and hard, that of the other reddish and brittle. The acorns are sometimes used to feed swine. The bark is employed in tanning, and as a coarse kind of febrifuge. Oak sawdust is an ingredient in dyeing a fustian-color, also drab and brown. The decaying leaves produce heat by fermentation. Also the genus Quercus; or a species or genera more or less resembling the oak; as, the Australian Casuarina.