Greek grammatical discussion of words ending in -ος and -βος (and related suffixes), focusing on accentuation rules for adjectives and proper names and giving numerous place-name examples.
Τὰ εἰς 'ος' καθαρὸν ἔχοντα δίφθογγον τὴν διὰ τοῦ 'υ' ὀξύνεται, ἐπιθετικὰ ὄντα ἢ κύρια ὁμοφωνοῦντα τοῖς ἐπιθέτοις, ἀκουός καὶ ἐπακουός, ἀγαυός καὶ τὸ κύριον καὶ τὸ ἐπίθετον. πρόσκειται «εἰ μὴ ἐπιθετικὰ εἴη, ἀλλὰ κύρια», ὅτι ταῦτα βαρύνεται, Ἀκάλαυος, Πείραυος, Ἄρευος. {1ΠΕΡΙ ΤΩΝ ΕΙΣ 'βος', ΕΙΣ 'γος' ΚΑΙ ΤΩΝ ΚΑΘΕΞΗΣ ΜΕΧΡΙ ΤΩΝ ΕΙΣ 'μος'. ΒΙΒΛΙΟΝ ϛʹ.}1 Τὰ εἰς 'βος' δισύλλαβα κύρια ἢ προσηγορικὰ βαρύνεται, ὄλβος, λίβος, Λέσβος καὶ ὁ κτιστὴς καὶ ἡ νῆσος, φλοῖσβος, θάμβος τὸ μονογενές, τάρβος. λέμβος, βόμβος, τύμβος, ῥύμβος, στίβος, τρίβος. Στρόβος πόλις Μακεδονίας. Τάβος ἥρως, ἀφ´ οὗ Τάβαι πόλις Λυδίας. Θράμβος ἀκρωτήριον Μακεδονίας. Ἴσβος Ἰσαυρίας πόλις, Κύβος ἢ καὶ Κυβώ, πόλις Ἰώνων ἐν Λιβύῃ Φοινίκων, Ὄμβοι πόλις Αἰγύπτου πρὸς τῇ Λιβύῃ. Ἀλέξανδρος ἐν πρώτῳ Αἰγυπτιακῶν. Σάβοι ἔθνος Φρυγίας. λέγονται καὶ ἀντὶ τοῦ βάκχοι παρὰ Φρυξίν. Σάμβος πόλις Ἀράβων καὶ οἱ πολῖται Σάμβοι. Βοῖβος Γλαφύρου υἱός, ἀφ´ οὗ Βοίβη πόλις Θεσσαλίας. Στροῖβος ὁ ἀδελφὸς Γύζαντος. σεσημείωται τὸ Βόλβος παροξυνόμενον, ὅτε κύριον, βολβός δὲ τὸ προσηγορικόν, ὥσπερ λοβός μέρος τοῦ ἥπατος. Τὰ εἰς 'βος' δισύλλαβα ἐπιθετικὰ ὀξύνεται, στραβός, ῥαιβός ὁ μὴ ὀρθός, καὶ κωβός.
Nouns in -ος with a pure diphthong, the one written with υ, are accented on the last syllable when they are adjectival, or proper names that are homophonous with the adjectives: ἀκουός and ἐπακουός, ἀγαυός both as a proper name and as an adjective. The proviso is added, “unless they are not adjectival but proper names,” because these are accented with a grave: Ἀκάλαυος, Πείραυος, Ἄρευος.
{1ON WORDS IN -βος, IN -γος, AND THE FOLLOWING DOWN TO THOSE IN -μος. BOOK 6.}1 Disyllabic words in -βος, whether proper names or appellatives, are accented with a grave: ὄλβος, λίβος, Λέσβος both the founder and the island, φλοῖσβος, θάμβος the only-begotten, τάρβος; λέμβος, βόμβος, τύμβος, ῥύμβος, στίβος, τρίβος. Στρόβος, a city of Macedonia. Τάβος, a hero, from whom Τάβαι, a city of Lydia. Θράμβος, a promontory of Macedonia. Ἴσβος, a city of Isauria; Κύβος or also Κυβώ, a city of the Ionians in Libya of the Phoenicians; Ὄμβοι, a city of Egypt near Libya. Alexander in the first book of the Egyptian Affairs. Σάβοι, a people of Phrygia; they are also said among the Phrygians in place of βάκχοι. Σάμβος, a city of the Arabs, and the citizens are Σάμβοι. Βοῖβος, son of Γλαφύρος, from whom Βοΐβη, a city of Thessaly. Στροῖβος, the brother of Γύζας. It is noted that Βόλβος is accented on the penult when it is a proper name, but βολβός is the appellative, just as λοβός is a part of the liver. Disyllabic adjectives in -βος are accented on the last syllable: στραβός, ῥαιβός, “not straight,” and κωβός.