The lemon is a small evergreen tree (Citrus limon) originally native to Asia, and is also the name of the tree’s oval yellow fruit.
The fruit is used for culinary and nonculinary purposes throughout the world – primarily for its juice, though the pulp and rind (zest) are also used, mainly in cooking and baking.
Lemon juice is about 5% (approximately 0.3 mole per litre) citric acid, which gives lemons a sour taste, and a pH of 2 to 3. This makes lemon juice an inexpensive, readily available acid for use in educational science experiments.
Because of the sour flavor, many lemon-flavored drinks and candies are available, including lemonade.