Citron

The Citron Citrus medica is a species of citrus fruit. It is characterized by its thick rind and small sections. Generally, it is eaten preserved or in bakery goods, such as fruitcakes. (The candied peel rather than the fruit is often used in cooking.)

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 called a "limon", so there is a high chance for getting things mixed up during translations. See false friend.