The lemon, Citrus limon (L.), is a species of small evergreen tree in the flowering plant family Rutaceae, native to Asia. It is an oval shaped, yellow citrus fruit with with smooth porous skin. It has a bright yellow skin that can be thin and lightly textured or thick and heavier textured. It has a pointed tip on the bottom of the fruit. Lemon has many varieties few of which includes Bush lemon, Eureka, Lisbon, Ponderosa, Variegated Pink, Verna, Villafranca, Yen Ben and Yuzu. The colour range of lemon fruit is from greenish yellow to bright yellow depending on the maturity. The top producers of lemon include India, Mexico, Argentina, Brazil, Spain, China, United States, Turkey, Iran and Italy.

Lemons are very high in vitamin C which protects against various diseases, for example scurvy and contributes to a strong immune system. It contains flavonoids which provide soothing relief for coughs, sore throats, and flu symptoms. Lemons can be used in home beauty treatments to rejuvenate the skin and is found in many commercial beauty products.

The juice of the lemon consisted of about 5-6 % citric acid, with a pH of around 2.2, giving it a sour taste. The distinctive sour taste of lemon juice makes it a key ingredient in drinks and foods. Lemonade, made with lemon, sugar, and water, is a popular warm-weather beverage, and the juice itself is commonly added to tea to make ice lemon tea.

Throughout the world, the fruit can be used for culinary and non-culinary purposes. Primarily it is used for its juice through the pulp and peel is also used mainly in cooking and baking. Lemon peel which is considered a waste, can be used to prepare oil, used in perfumes, soap, and flavouring purposes. Pectin can be extracted from lemon peel as gelling agent and also used in medicine in the treatment of intestinal disorders.

Lemon is often used to flavor many sweet and savory dishes. They are used in sauces or as an accompaniment to fish and poultry. Sauces and foods containing lemon juice help in the digestion of fried foods. Lemons are also used in baked goods and desserts to provide a light, fresh flavor.

Besides adding flavor, lemons are used for other purposes when preparing food. Their high content of vitamin C is important to prevent the discoloring of the flesh of fruits and vegetables that oxidize quickly when exposed to the oxygen in the air. Lemon juice can be used to tenderize meat or it can be used as a alternative to vinegar in dressings. Lemon juice added to steamed vegetables will help them maintain their bright colors and enhance their flavor.