Discussion of accentuation patterns in Ancient Greek for adjectives, epithets, and proper names with endings like -ενος, -ηνος, -ινος, -υνος; specifies when disyllables are oxytone or barytone with place-name and adjective examples.
ἐπιθετικὰ ἢ προσηγορικὰ ἔχοντα διαστολὴν ὀξύνεται, φανός. τὸ δὲ πλάνος βαρύνεται καὶ τὸ νᾶνος ὁ μικρός. Τὰ εἰς 'ενος' δισύλλαβα τινὰ μὲν βαρύνονται, ἔνος ὁ ἐνιαυτός, ξένος, Τένος ὁ Κύκνου, τινὰ δὲ ὀξύνονται, κενός, στενός. Τὰ εἰς 'ηνος' κύρια ἢ προσηγορικὰ βαρύνεται, Τῆνος, νῆσος Κυκλὰς ὁμοφώνως τῷ οἰκιστῇ. ἔστι καὶ πόλις Λακωνικὴ μία τῶν ἑκατὸν Τῆνος λεγομένη, Φῆνος ὄνομα ποταμοῦ, Ῥῆνος ὁ ποταμὸς καὶ ἔθνος παροικοῦν. Στρῆνος πόλις Κρητική, Λῆνος ὁ τόπος τῶν Πισατῶν. Φλέγων μηʹ Ὀλυμπιάδι. Σῆνος πόλις Αἰγύπτου. Ἑκαταῖος ἐν αὐτῆς περιηγήσει, Ἦνος, Σφῆνος ὄνομα τόπου, Σμῆνος ὄνομα ποταμοῦ, Γλῆνος ὄνομα πόλεως Κρητικῆς, Μῆνος, θρῆνος. τὰ δὲ ἐπίθετα ὀξύνεται, φηνός ὁ λαμπρός, στρηνός, πτηνός, ψηνός. ἔτι καὶ τὸ ληνός μὴ ὂν ἐπίθετον. Τὰ εἰς 'ινος' δισύλλαβα βαρύνεται, Νίνος πόλις Ἀσσυρίων, ἣν ἔκτισε Νίνος Σεμιράμιδος ἀνήρ, ἐν τῇ Ἀτουρίᾳ. πίνος ὁ ῥύπος, δῖνος ἡ συστροφή, σχῖνος, λίνος ὃ σημαίνει εἶδος ὕμνου ὡς παιάν, διθύραμβος, σπίνος εἶδος ὀρνέου «καὶ σπίνος ἠῷα σπίζων καὶ ὄρνεα πάντα» παρ´ Ἀράτῳ (Dios. 292). Σπῖνος ποταμός, γρῖνος, πρῖνος. μόνον τὸ ῥινός ὀξύνεται «ἕσσατο δ´ ἔκτοσθεν ῥινόν» (Κ 334). τὸ δὲ κλεινός, αἰνός, δεινός ὀξύνεται μὴ ἔχοντα τὸ 'ι' μόνον. τὸ δὲ αἶνος ἐπὶ τοῦ ὕμνου ἐπί τε τῆς πόλεως βαρύνεται. Τὰ εἰς 'υνος' δισύλλαβα, εἰ μὴ κύρια εἴη, ὀξύνεται, θυνός, ξυνός, γρυνός ἡ ῥίζα τῶν ξύλων ἡ ξηρὰ καὶ παχεῖα, πλυνός, φρυνός ὁ βάτραχος. τὰ δὲ κύρια βαρύνεται, Κῦνος ἐπίνειον Ὀποῦντος,
Adjectival or appellative words that have a distinguishing mark are accented with an acute: φανός. But πλάνος is accented with a grave, and likewise νᾶνος, ‘the small one.’
Among the disyllables in -ενος, some are accented with a grave: ἔνος, ‘the year’; ξένος; Τένος, the (island) of Cycnus; but some are accented with an acute: κενός, στενός.
Proper names or appellatives in -ηνος are accented with a grave: Τῆνος, a Cycladic island, homophonous with its founder. There is also a Laconian city, one of the hundred, called Τῆνος; Φῆνος, the name of a river; Ῥῆνος, the river and the people dwelling beside it; Στρῆνος, a Cretan city; Λῆνος, the place of the Pisatans—Phlegon in the 48th Olympiad; Σῆνος, a city of Egypt—Hecataeus in his Periegesis; Ἦνος; Σφῆνος, the name of a place; Σμῆνος, the name of a river; Γλῆνος, the name of a Cretan city; Μῆνος; θρῆνος. But the adjectives are accented with an acute: φηνός, ‘bright’; στρηνός; πτηνός; ψηνός; and also ληνός, though it is not an adjective.
Disyllables in -ινος are accented with a grave: Νίνος, a city of the Assyrians, which Ninus, the husband of Semiramis, founded in Aturia; πῖνος, ‘dirt’; δῖνος, ‘a whirl’; σχῖνος; λίνος, which means a kind of hymn, like παιάν, διθύραμβος; σπῖνος, a kind of bird: «καὶ σπῖνος ἠῷα σπίζων καὶ ὄρνεα πάντα» in Aratus (Dios. 292); Σπῖνος, a river; γρῖνος; πρῖνος. Only ῥινός is accented with an acute: «ἕσσατο δ᾽ ἔκτοσθεν ῥινόν» (Κ 334). And κλεινός, αἰνός, δεινός are accented with an acute, not having only the ι. But αἶνος, in the sense of ‘hymn’ and also of the city, is accented with a grave.
Disyllables in -υνος, unless they are proper names, are accented with an acute: θυνός, ξυνός, γρυνός, ‘the dry and thick root of trees’; πλυνός; φρυνός, ‘the frog.’ But the proper names are accented with a grave: Κῦνος, the harbor-town of Opus.