σελήνη

σελήνη (selene, "seh-LAY-nay") is the Greek word for the moon, and the record places it, strikingly, less among poets than among philosophers and astronomers. It appears 219 times across 56 works, and the heaviest concentration is in Diogenes Laertius's Lives of Eminent Philosophers (50) — where the moon is a thing to be theorized. After that come Aristotle's Analytica priora et posteriora (18), Plotinus's Enneads (13), Aristotle's Metaphysics (12), the De Mundo (9), and Plato's Laws (9). The moon in this corpus is chiefly an object of argument and cosmology, not of lament.

The lexica agree on the plain sense. LSJ (Liddell–Scott–Jones, 1940) gives "the moon," and preserves the Homeric phrase σελήνη πλήθουσα (selene plethousa, "the full moon," Iliad 18.484), along with its later technical life — "a moon's breadth," a unit of measure used by early astronomers. Beekes (Etymological Dictionary of Greek, Brill 2010), Chantraine (Dictionnaire étymologique, 1968–80), and Frisk (Griechisches etymologisches Wörterbuch, 1960–72) all gloss it "moon" and each records the dialect forms: Doric σελάνα (selana) and Aeolic σελάννα (selanna, the form Sappho used). Beekes and Frisk both note the negated compound the Greeks built from it, ἀ-σέληνος (aselenos, "moonless"), attested in Thucydides.

On the deeper root, the record is honest about its limits. Three etymology pointers are matched — to Beekes, Chantraine, and Frisk — but they mark where the word is treated, not a settled reconstruction; Frisk even flags the derivation as "sehr problematisch" ("very problematic") and pre-Greek. What the record firmly supports is the derived doublet σελήνη / σελαναία (selanaie), the epic-poetic byform seen since the Iliad.

The citable surfaces carry the word into Scripture: 1 Corinthians 15.41, where "the glory of the moon" ranks among sun, moon and stars, and Acts 2.20, where the moon turns to blood. In Aeschylus's Agamemnon (296–299) it lights the beacon-chain.

If the moon lives here mostly inside proofs and cosmologies, is it the same moon the poet meant by πλήθουσα, "full"?