Citron is a large, yellow citrus fruit that resembles a lemon but is much bigger and has a thicker rind. It is known scientifically as Citrus medica and is one of the oldest cultivated citrus fruits. Citron has a bumpy, textured skin and is primarily grown in tropical and subtropical regions. The fruit is not typically eaten raw due to its sour taste and thick pith. Instead, it is often used in cooking, especially in Jewish traditions during the festival of Sukkot, where it is one of the four species used in rituals. Citron is also used to make candied peel and essential oils.