Chestnut which are mildly poisonous to humans. Nor should they be confused with water chestnut, which are tubers of an aquatic herbaceous plant in the sedge family Cyperaceae. Other trees commonly mistaken for chestnut trees are the chestnut oak ("Quercus prinus") and the American beech ("Fagus grandifolia"), both of which are also in the Fagaceae. The name "chestnut" is derived from an earlier English term "chesten nut", which descends from the Old French word "chastain" (Modern French, "châtaigne"). The French word in turn derives from Latin "Castanea" (also the scientific name of the tree), which traces to the Ancient Greek word
Fagus sylvatica depends on the location: in forest areas, "F. sylvatica" grows to over , with branches being high up on the trunk. In open locations, it will become much shorter (typically ) and more massive. The leaves are alternate, simple, and entire or with a slightly crenate margin, 5–10 cm long and 3–7 cm broad, with 6–7 veins on each side of the leaf (7–10 veins in "Fagus orientalis"). When crenate, there is one point at each vein tip, never any points between the veins. The buds are long and slender, long and thick, but thicker (to ) where the buds