Plutarch, De Iside et Osiride
Goodwin, Ed.

But Osiris had his name from ὅσιος and ἱερός (pious and sacred) compounded; for he is the common idea of things in heaven and things in the lower world, the former [p. 120] of which the ancients thought fit to style ἱερά, and the latter ὅσια. But the principle which discloses things heavenly, and which appertains to things whose motion tends upwards (ἄνω), is called Anubis, and sometimes he is also named Hermanubis, the former name referring to things above, and the latter to things beneath. For which reason they also sacrifice to him two cocks, the one whereof is white and the other of a saffron color, as esteeming the things above to be entire and clear, and the things beneath to be mixed and various. Nor need any one to wonder at the formation of these words from the Grecian tongue; for there are many thousand more of this kind, which, accompanying those who at several times removed out of Greece, do to this very day sojourn and remain among foreigners; some whereof when poetry would bring back into use, it hath been falsely accused of barbarism by those men, who love to call such words strange and outlandish. They say, moreover, that in the so-called books of Hermes there is an account given of the sacred names; and that power which presides over the circulation of the sun is called Horus, and by the Greeks Apollo; and that which is over the winds is by some called Osiris, and by others Serapis, and by others again in the Egyptian tongue Sothi. Now the word Sothi signifies in Greek to breed (κύειν) and breeding; and therefore, by an obliquation of the word κύειν, the star which they account proper to the Goddess Isis is called in Greek κύων, which is as well dog as breeder. And although it be but a fond thing to be over contentious about words, yet I had rather yield to the Egyptians the name of Serapis than that of Osiris, since I account the former to be foreign, and the latter to be Greekish, but believe both to appertain to one God and to one power.