Citron
A source of confusion is that "citron" or similar words in French (and other languages), and English are false friends, as they refer to the lemon. Indeed, into the 16th century, the English name "citron" included the lemon and perhaps the lime as well.
Citrus depressa
Citrus depressa ("Citrus" × "depressa", formerly "C. pectinifera", "shiikwaasa", "hirami remon" or "shīkuwāsā"), in English sometimes called shiikuwasha, shequasar, Taiwan tangerine, flat lemon, hirami lemon, or thin-skinned flat lemon, is a small, green citrus fruit rich in flavonoids and native to Taiwan and Okinawa, Japan.