Citron is a citrus fruit of the species Citrus medica. It is characterized by its thick rind and small sections. Generally, it is eaten preserved or in bakery goods, such as fruitcakes.

The citron is known as the etrog by religious Jews, who use it in a ceremony on their Sukkot holiday each fall.

In many non-English languages, a normal lemon is called a "citron" and a lime is caled a "limon", so there is a high chance for getting things mixed up during translations. See false friend.