A genus, Fagus, of deciduous trees of the beech family Fagaceae, order Fagales. They can best be distinguished by their long (often more than 1 in. or 2.5 cm), slender, scaly winter buds; their thin, gray bark, smooth even in old trees; and their simple, toothed, ovate or ovate-oblong, deciduous leaves.

The American beech (F. grandifolia) is native in the United States east of the Mississippi River and in the lower Mississippi Valley. The hard, strong wood is used for furniture, handles, woodenware, cooperage, and veneer. The small, edible, three-sided nuts, called beechnuts, are valuable food for wildlife. The European beech (F. sylvatica) is more popular as an ornamental tree than the American species. Its leaves are smaller, with 5–9 pairs of primary veins compared with 9–14 pairs in the American beech. The leaf teeth are also shorter. Important ornamental varieties are F. sylvatica purpurea, the copper or purple beech; var. incisa, the cut-leaved or fern-leaved beech; and F. pendula, the weeping European beech.