The durian is the fruit of several tree species belonging to the genus Durio and the Malvaceae family (although some taxonomists place Durio in a distinct family, Durionaceae. Widely known and revered in southeast Asia as the "king of fruits", the durian is distinctive for its large size, unique odour, and formidable thorn-covered husk. The fruit can grow as large as 30 centimetres (12 in) long and 15 centimetres (6 in) in diameter, and it typically weighs one to three kilograms (2 to 7 lb). Its shape ranges from oblong to round, the colour of its husk green to brown, and its flesh pale yellow to red, depending on the species.
The edible flesh emits a distinctive odour, strong and penetrating even when the husk is intact. Some people regard the durian as fragrant; others find the aroma overpowering and offensive. The smell evokes reactions from deep appreciation to intense disgust, and has been described variously as almonds, rotten onions, turpentine and gym socks. The odour has led to the fruit's banishment from certain hotels and public transportation in southeast Asia.
The durian, native to Brunei, Indonesia and Malaysia, has been known to the Western world for about 600 years. The 19th-century British naturalist Alfred Russel Wallace famously described its flesh as "a rich custard highly flavoured with almonds". The flesh can be consumed at various stages of ripeness, and it is used to flavour a wide variety of savoury and sweet edibles in Southeast Asian cuisines.