Lemon, (Citrus ×limon), small tree or spreading bush of the rue family (Rutaceae) and its edible fruit. Lemon juice is a characteristic ingredient in many pastries and desserts, such as tarts and the traditional American lemon meringue pie. The distinctive astringent flavour of the fruit, either fresh or preserved, is also used to enhance many poultry, fish, and vegetable dishes worldwide. Lemonade, made with lemon, sugar, and water, is a popular warm-weather beverage, and the juice itself is commonly added to tea. Citric acid may amount to 5 percent or more by weight of the lemon’s juice, which is also rich in vitamin C and contains smaller amounts of the B vitamins, particularly thiamin, riboflavin, and niacin.