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.
Greek citron
It was also called "pitima", or the "cedro col pigolo" ("citron with a pitom), because its usually persisting pitom (carpel). The last does not only enhance its character, but also adds Halachic promotion.