The almond is a small deciduous tree, growing to between 4 and 10 meters in height, with a trunk of up to 30 centimetres in diameter. The fruit is a drupe 3.56 cm long, with a downy outer coat. The outer covering or exocarp, fleshy in other members of Prunus such as the plum and cherry, is instead a leathery grey-green coating called the hull, which contains inside a hard shell, and the edible seed, commonly called a nut in culinary terms. Generally, one seed is present, but occasionally there are two. In botanical terms, an almond is not a true nut.