Discussion of Greek nouns in -ρος: accentuation patterns, syllable weight changes, and derivations from verbs, with examples (e.g., σπόρος, φθόρος, μόρος, φορός) and dialectal variants.
Ἶρος τὸ κύριον καὶ πόλις Θεσσαλίας. Λυκόφρων «Ἶρόν τε Τραχῖνα καὶ Περραιβικήν» (v. 905), Πῖρος, Τίρος, Σκίρος τὸ κύριον. ἔστι δὲ ἥρως, ἀφ´ οὗ Σκίρον τόπος Ἀττικός, καὶ Ἀρκαδίας κατοικία πλησίον Μαιναλέων καὶ Παρρασίων. εἰ μέντοι προσηγορικὰ ἢ ἐπιθετικὰ εἴη, ὀξύνεται, ἱρός ὁ ἱερός, λιρός ὁ ἀναιδής, σιρός τὸ προσηγορικὸν ὁ κατώγειος οἶκος. Τὰ εἰς 'ρος' δισύλλαβα παραληγόμενα τῷ 'ο' βαρύνεται, ὁπότε γίνεται ἀπὸ τῶν παραληγομένων τῷ 'ε' ἢ 'ει' ἢ 'αι' διφθόγγῳ ῥημάτων, εἰ μή τις διαστολὴ γένοιτο, σπόρος, ὅτι σπείρω, πτόρος ὁ πταρμός, ὅτι πταίρω, φθόρος ὅτι φθείρω, μόρος ὅτι μείρω, κόρος ὅτι κείρω, φόρος ὅτι φέρω, φορός δὲ ὁ ἄνεμος ὀξυτόνως, ὅρος, εἴρω γάρ, ὀρός δὲ τὸ ἀφυλιζόμενον τοῦ γάλακτος. τὸ δὲ ὄρρος βαρυτόνως καὶ κατὰ τὴν διάλεκτον καὶ τῷ λόγῳ· τὰ γὰρ εἰς 'ος' μονογενῆ δισύλλαβα τῷ 'ο' παραληγόμενα ἢ ἐξ αὐτοῦ ἀρχόμενα καὶ ἔχοντα δὶς τὸ αὐτὸ σύμφωνον βαρύνεται, κόννος, κόκκος, κόττος, ὄσσος· οὕτως ἄρα καὶ ὄρρος· τὸ μέντοι βορός ὁ πολλὰ ἐσθίων καὶ τὸ χορός καὶ σορός ὁ τάφος καὶ τορός ὀξύνονται· οὐ γὰρ γίνονται ἀπὸ τοιούτων ῥημάτων, ἀλλὰ τὸ βορός ἀπὸ τοῦ βρῶ βρώσω βρώσκω, καὶ τὸ χορός ἀπὸ τοῦ χωρῶ, χῶρος, χορός τροπῇ τοῦ 'ω' εἰς 'ο', καὶ τὸ σορός ἀπὸ τοῦ σωρεύω σωρεός σωρός ἀρσενικῶς καὶ σορός θηλυκῶς καὶ τὸ τορός δὲ ἀπὸ τοῦ τρῶ. σεσημείωται τὸ δορός ὁ δεδαρμένος, εἰ καὶ ἐκ τοῦ δείρω γίνεται.
Ἶρος is a proper name and a city of Thessaly. Lycophron: «Ἶρόν τε Τραχῖνα καὶ Περραιβικήν» (v. 905); likewise Πῖρος, Τίρος, Σκίρος are proper names. There is also a hero, from whom comes Σκίρον, an Attic place, and a settlement of Arcadia near the Maenalians and Parrhasians. If, however, they are appellatives or adjectival, they are accented with an acute: ἱρός ‘the sacred’, λιρός ‘the shameless’, σιρός, the appellative, ‘the underground storehouse’. Disyllables in -ρος with penult in ο are accented with a grave, whenever they are formed from verbs whose penult has ε or ει or the diphthong αι, unless some distinction arises: σπόρος, because of σπείρω; πτόρος ‘sneezing’, because of πταίρω; φθόρος, because of φθείρω; μόρος, because of μείρω; κόρος, because of κείρω; φόρος, because of φέρω; but φορός ‘wind’ with an acute; ὅρος, for it is from εἴρω; but ὀρός is the whey separated from milk. But ὄρρος is with a grave both according to dialect and according to principle; for disyllabic monogender nouns in -ος with penult in ο, or beginning with ο and having the same consonant twice, are accented with a grave: κόννος, κόκκος, κόττος, ὄσσος; therefore likewise ὄρρος. But βορός ‘one who eats much’ and χορός and σορός ‘tomb’ and τορός are accented with an acute; for they are not formed from such verbs, but βορός from βρῶ, βρώσω, βρώσκω, and χορός from χωρῶ: χῶρος, χορός by changing ω to ο; and σορός from σωρεύω: σωρεός, σωρός in the masculine and σορός in the feminine; and τορός too from τρῶ. Noted as exceptional is δορός ‘flayed’, although it is formed from δείρω.