The lemon is a yellow oval-shaped acidic citrus fruit that averages several inches in length.
The fruit has a tart taste, so although it can be eaten straight, it is rarely used so, and more often cooked into other dishes, used as a garnish on foods (such as fish), or made into soup or drinks such as lemonade and lemon tea. 
Lemons are high in Vitamin C (ascorbic acid) and helped to prevent the disease of scurvy in the 18th Century. Oil from the lemon seed and peel have also long been used for medicinal purposes and to relieve some disease symptoms. Lemon oil is also used in some cleaning products and perfumes. 
Lemons have long been grown in India and Egypt. They were believed to have been introduced into Europe near the end of the 12th century, gained popularity in Italy and Spain, and brought to the Americas in the 1490's by Christopher Columbus. 
California is the leading state in the US that grows lemons for commercial purposes, followed by Arizona and Florida. The lemon tree usually reaches 10 to 20 feet in height. It is not tolerant of cold and requires a warm climate and sandy soil. 
Lemons in popular culture
A manufactured item that is plainly faulty, such as a car that needs a great deal of repair work while it is still new, is sometimes known as 'a lemon'.
A popular saying is, "When life throws you lemons, make lemonade."