The citron (κίτρον, κίτριον); Citrusfruit of a tree of the orange and lemon family. It is oblong in shape, and sometimes as much as six inches in length. The skin is thick, somewhat hard, fragrant, and covered with protuberances; the pulp is white and subacid. Modern naturalists assume the north of India to be its native home; but it passed to the countries of the Mediterranean from Media or Persia ; hence the name of the tree, "Citrus medica," and of the fruit, "Malum medica," or "Malum Persica"
It is therefore possible that the Jews brought the tree with them from Babylonia to Eretz Yisrael on their return from the Babylonian Captivity.