Accentuation rules for Greek nouns ending in -αος, -λεος, -νεος, and -ος, with examples (personal names, place-names) and notes on changes and variants.
* Τὰ εἰς 'αος' ὑπερτρισύλλαβα προπαροξύνεται οἷον Ἀμφιάραος, Μενέλαος· ἔστι καὶ πόλις Αἰγύπτου· Στράβων ἑπτακαιδεκάτῃ. Οἰνόμαος υἱὸς Ἁρπίνης τῆς Ἀσωποῦ καὶ Ἄρεος. Τὰ διὰ τοῦ 'λεος' τρισύλλαβα ἁπλᾶ ὀξύνεται, μὴ ὄντα κτητικὰ ἢ διαφόρως τονούμενα πρὸς διάφορον σημασίαν, εἰλεός ἡ κατάδυσις καὶ ἡ νόσος καὶ ἡ μαγειρικὴ τράπεζα, φωλεός, κολεός, Μαλεός, γαλεός ὁ ἀσκαλαβώτης. Φιλύλλιος Αἰγεῖ «ὁ πάππος ἦν μοι γαλεὸς ἀστερίας» καὶ Ἄρχιππος Ἰχθύσιν «τί λέγεις σύ; μάντεις εἰσὶ γὰρ θαλάττιοι; γαλεοί γε πάντων μάντεων σοφώτατοι». ἀλεός καὶ Ἀλεός ὁ πολίτης Ἀλέας ὁμοφώνως τῷ οἰκιστῇ, παλεός. Κελεός, Πελεός, Ἐλεός δὲ τὸ κύριον καὶ ἐπίθετον, ἔλεος δὲ τὸ προσηγορικόν. τὸ δὲ μέλεος σύνθετόν ἐστι. τὸ δὲ τέλεος καὶ κήλεος κατὰ πάθος ἀπὸ τέλειος καὶ κήλειος κτητικά. * Τὰ εἰς 'νεος' ὑπὲρ δύο συλλαβὰς ὀξύνεται, ἐνεός, Φενεός ἥρως καὶ πόλις Ἀρκαδίας· «οἳ Φενεόν τ´ ἐνέμοντο καὶ Ὀρχομενόν »(Β 605). λέγεται καὶ ἀρσενικῶς καὶ θηλυκῶς. κενεός, ἀφνεός, Ἐλινεός ὄνομα ἔθνους. Ἐρινεός πόλις Δωριέων ὑπὸ τὸν Παρνασσόν. λέγεται καὶ Ἐρινειός. ἔστι καὶ Θετταλίας ἄλλη καὶ Ἀχαΐας. τὸ δὲ λαΐνεος καὶ ἐλαΐνεος κατὰ πλεονασμὸν τοῦ 'ε' ἐκ τοῦ λάϊνος καὶ ἐλάϊνος. τὸ δὲ κυάνεος κτητικὸν ἀποβολὴν ἔπαθε τοῦ 'ι' ἀπὸ τοῦ κυάνειος γεγονός. * Τὰ εἰς 'ος' λήγοντα ὀνόματα παρὰ ῥῆμα γινόμενα καθαρεύοντα καὶ τῷ 'ε' παραληγόμενα ὀξύνεσθαι θέλει, φωλεύω, φωλεός, ὀχεύω ὀχεός καὶ ἐν πλεονασμῷ τοῦ 'σ' ὀσχεός. καὶ παρὰ σωρεύω δὲ ὁ σωρεός. τὸ δὲ σωρός κατὰ συγκοπὴν ἀπετελεῖτο. καὶ παρὰ τὸ λοχεύω
Words in -αος with more than three syllables are accented on the antepenult, e.g. Ἀμφιάραος, Μενέλαος; there is also a city of Egypt (so Strabo in book 17): Οἰνόμαος, son of Ἁρπίνη daughter of Ἀσωπός and Ἄρης. Simple trisyllables in -λεος are accented on the ultima, provided they are not possessives or differently accented to mark a different meaning: εἰλεός, ‘a diving down’ and ‘a disease’ and ‘a cook’s table’; φωλεός, κολεός, Μαλεός, γαλεός ‘the gecko’. Philullius in Aegeus says, “my grandfather was a γαλεὸς ἀστερίας,” and Archippus in Fishes, “what are you saying? are there sea-prophets? yes indeed—γαλεοί are the wisest of all prophets.” ἀλεός, and Ἀλεός, the citizen of Ἀλέα, with the same sound as the founder; παλεός. Κελεός, Πελεός; Ἐλεός is the proper name and the adjective, but ἔλεος is the appellative. μέλεος is a compound. τέλεος and κήλεος are, by affection, possessives from τέλειος and κήλειος. Words in -νεος with more than two syllables are accented on the ultima: ἐνεός; Φενεός, a hero and a city of Arcadia: “who dwelt in Φενεόν and Ὀρχομενόν” (Β 605). It is said both in the masculine and in the feminine. κενεός, ἀφνεός; Ἐλινεός, the name of a people. Ἐρινεός, a city of the Dorians under Parnassus; it is also called Ἐρινειός. There is also another in Thessaly and in Achaea. λαΐνεος and ἐλαΐνεος, by addition of ε, are from λάϊνος and ἐλάϊνος. κυάνεος, a possessive, has undergone loss of ι, having come from κυάνειος. Nouns ending in -ος that are formed from a verb, with pure vowels and with ε in the penult, want to be accented on the ultima: φωλεύω, φωλεός; ὀχεύω, ὀχεός, and with addition of σ, ὀσχεός. Also from σωρεύω comes σωρεός; but σωρός was produced by syncope. And from λοχεύω…