In Hebrew, the citron is transliterately known as the etrog meaning love and attraction in Talmudical Aramic, The Arabic name for the fruit itranj اترنج is also cognate with the Hebrew; the itranj is mentioned favorably in the Hadith. It is one of the Four Species used during the holiday of Sukkot each fall. The role of the citron in that holiday was portrayed in the Israeli movie Ushpizin. Citrons that have been bred with lemon (in order to increase output per tree and make the tree less fragile) are not kosher for use as part of the Four Species.
In Tamil, the unripe fruit is referred to as 'narthangai', which is usually salted and dried to make a preserve. The tender leaves of the plant are often used in conjunction with chili powder and other spices to make a powder, called 'narthellai podi', literally translating to 'powder of citron leaves'. Both narthangai and narthellai podi are usually consumed with thayir sadam.
The East Asian citrus fruit yuzu (also called yuja) is sometimes called a citron, it is actually a separate species, Citrus junos.