A night (νύξ) in Homer is dark, especially in the Iliad, even black, murky, moonless (μέλαινα, ἐρεβεννή, ὀρφναίη, κελαινή, δνοφερή, σκοτομήνιος, ἐρεμνή). It may be baneful, bad, sleepless, cold, a source of pain, especially in the Odyssey (ὀλοή, κακή, ἄυπνος, πηγυλίς, δυσκηδέα). Black night will cover the earth, or a battle, perhaps drawn over it by a god; it enfolds the eyes of men slain. In the night men and gods sleep or wake, dreams come, Zeus rains and blows, or thunders and devises evil; men feast, lie awake pondering, walk about to rouse others, or lament their dead; lions menace flocks, fires burn, ships sail or come to harbor, wanderers are a danger; Odysseus lies with Calypso, Penelope unravels her web. There is one great nighttime adventure, the daring raid by Odysseus and Diomedes in Iliad 10.
Night is the subduer (δμήτειρα) of gods and men, and even angry Zeus hesitates to displease swift Night (Il. 14.256–261), which “it is good to obey,” ἀγαθὸν καὶ νυκτὶ πιθέσθαι (7.293, etc.). Swift it is, as when it rushes from heaven in the Odyssey—ὀρώρει δ᾽ οὐρανόθεν νύξ (Od. 5.294, etc., whence Vergil’s ruit Oceano nox)—each time with dark portent. Thus in force and speed it is divine, or like the divine; and when Apollo strides down from Olympus in wrath against the Achaeans, he comes like the night, ὃ δ᾽ ἤϊε νυκτὶ ἐοικώς (Il. 1.47). Likewise the phantom of Heracles in Hades is like dark night (Od. 11.606), and the face of nearly-superhuman Hector leaping inside the Achaean gate is like swift night (Il. 12.463).
The most glorious of nights is that in which the Trojan fires shine like the stars about the moon as they are seen when “from heaven breaks open the infinite air” (οὐρανόθεν δ᾽ ἄρ᾽ ὑπερράγη ἄσπετος αἰθήρ, Il. 8.558, trans. Murray, rev. Wyatt). The longest nights are the ones in which Odysseus and the swineherd tell their tales, Odysseus first to the Phaeacians—“This night is very long,” says their king, “ἀθέσφατος,” apparently meaning “beyond even a god’s power to express”—then Eumaeus to Odysseus, with the same adjective, and lastly Odysseus again to Penelope, when Athene herself holds back the dawn, in a divine action surpassing words. If the unspeakable is what is inexpressible by logos (which is Latin ratio), hence (so to speak) “irrational,” and ἀθέσφατος is beyond even divine speech, one might (with a nod to the mathematicians) privately render it “transcendental.”
Finally, there is the favorite epithet of night, “ambrosial,” ἀμβροσίη. What does it mean? “Fragrant,” “divine,” like ambrosia, the food of the gods, which also cleanses, perfumes, and preserves corpses; as divine, so “immortal,” i.e. not βροτός (or an assumed form μροτός, mrotos, like mortal); a time for gods, not men, as anxious Achaean chiefs suggest in Iliad 10 (41, 142), and Hermes makes plain in Iliad 24 (363), asking Priam why he is traveling “through the ambrosial night when other mortals are sleeping.” On this word there are excellent discussions in W. B. Stanford’s The Odyssey of Homer (consult the Greek indexes to the two volumes). But before leaving it I want to point out that even the rugged Cyclopes call the night ambrosial, following the expression with a reference to mortals, as if imitating the play on words once made by the divine messenger; and to them Polyphemus, speaking out of his own new darkness into the ancient great dark without, can only reply with the punning name by which Odysseus has pulled the wool over his eye.
And what about Vergilian nights?