Greek prosody: contraction, lengthening, and accentuation of υ and ο in various endings (-υς, -ος, -λος, -ιμος, -μος); lists examples and meter-based exceptions.
* Τὰ εἰς 'υς' θηλυκὰ ὀξύτονα διὰ τοῦ 'δ' κλινόμενα συστέλλονται, κροκύς κροκύδος, χλαμύς χλαμύδος, πηλαμύς πηλαμύδος. τὰ δὲ εἰς 'υς' θηλυκὰ ὀξύτονα διὰ καθαροῦ τοῦ 'ος' κλινόμενα ἐκτεταμένον ἔχουσι τὸ 'υ', πληθύς, ἐδητύς, ὀϊζύς, ἐρινύς, ἰξύς ἡ ῥάχις, ἰσχύς, ἰλύς, τὸ δὲ νηδύς ποιητικῇ ἀδείᾳ συστέλλεται. φιλεῖ δὲ τὸ 'υ' ἐπ´ εὐθείας ἐκτεινόμενον συστέλλειν τὰς ἄλλας πτώσεις οὐ μόνον ἐν τῷ πῦρ πυρός, ἀλλὰ καὶ ἐν τῷ ἰχθύος, δρυός, ἰσχύος, ἰλύος. ἐν δὲ τῷ «ἰλύος» (Φ 318) τὸ 'υ' ἐκτέταται διὰ τὸ μέτρον. * Τὰ εἰς 'υς' βαρύτονα εἴτε θηλυκὰ εἴτε ἀρσενικὰ συστέλλονται, γένυς, πίτυς, χέλυς, γῆρυς, ἀτράφαξυς, Πόλτυς, βότρυς, Ἕρπυς, Ἅλυς, ἥμισυς, πέλεκυς, Ῥαδάμανθυς. * Τὰ εἰς 'υς' ὀξύτονα ἐπιθετικὰ συστέλλεται, πολύς, ἠΰς, ἡδύς, βραδύς. * Τὰ εἰς 'υς' σύνθετα πάντα συνεσταλμένον ἔχει τὸ 'υ' καὶ προπαροξύνεται, σύνοφρυς, λεύκοφρυς, κάλλιχθυς, δίβραχυς. * Τὰ εἰς 'ος' ὀξύτονα ἀρσενικὰ δισύλλαβα καθαρὰ διχρόνῳ παραληγόμενα ἐκτείνει αὐτὸ οἷον ναός, λαός, κριός, ἰός πλὴν τοῦ βιός. * Τὰ εἰς 'ος' καθαρὸν ἀρσενικὰ δισύλλαβα εἰ παραλήγοι τῷ 'α', ἐκτείνει αὐτὸ ναός, λαός. δάος οὐδέτερον. σεσημείωται τὸ σάος. * Τὰ εἰς 'λος' λήγοντα δισύλλαβα ὀξύτονα, ὁπότε ἔχει πρὸ τέλους δίχρονον, τοῦτο ἔχει συνεσταλμένον ἢ ἐκτεινόμενον δι´ ἑαυτοῦ ἢ διὰ συμφώνου μεγεθυνόμενον. καὶ τὰ μὲν διὰ συμφώνων μεγεθυνόμενα τὰ τοιαῦτά ἐστι, κυλλός, μαλλός, θαλλός, τὰ δὲ δι´ ἑαυτῶν τὰ τοιαῦτα, ψιλός, χυλός, δαλός, βαλός, οὕτως ὁ βαθμός καὶ ἐν τῇ τραγῳδίᾳ καὶ ἐν τῇ κωμῳδίᾳ. ἐχρῆν οὖν καὶ τὸ καλός ἢ βοηθεῖσθαι συμφώνῳ ἢ αὐτόθεν ἐκτείνεσθαι. ὑγιὴς οὖν ἡ ἔκτασις παρὰ τῷ ποιητῇ. * Τὰ διὰ τοῦ 'ιμος' παραγωγὰ ὑπὲρ δύο συλλαβὰς συνεσταλμένον ἔχει τὸ 'ι', κύδιμος, ὠφέλιμος, ὤκιμος. τὸ μέντοι ἄτιμος ἐκτεῖνον τὸ 'ι' σύνθετόν ἐστιν. οὕτως δὲ ἀξιοῦται καὶ τὸ βούλιμος ἐκτείνεσθαι κατὰ τὴν δευτέραν συλλαβὴν συνθέτου ὑπάρχοντος τοῦ ὀνόματος· ἀντὶ γὰρ τοῦ ὁ μέγας λιμός. καὶ τὸ ἴφθιμος δὲ ἐκτείνει τὸ πρὸ τέλους 'ι'. Τὰ εἰς 'μος' καθαρὸν δισύλλαβα ἔχοντα τὸ 'υ' ἐκτείνουσιν αὐτὸ καὶ ὀξύνονται, χυμός, θυμός, δρυμός, ῥυμός. εἰ δὲ ὑπὲρ δύο συλλαβὰς ὑπάρχει, καὶ προπαροξύνεσθαι θέλουσι καὶ συστέλλουσι τὸ 'υ', εἰ μὴ
Feminine nouns in -υς that are oxytone and are declined with -δ- are shortened: κροκύς κροκύδος, χλαμύς χλαμύδος, πηλαμύς πηλαμύδος. But feminine nouns in -υς that are oxytone and are declined with pure -ος have υ lengthened: πληθύς, ἐδητύς, ὀϊζύς, ἐρινύς, ἰξύς “the spine,” ἰσχύς, ἰλύς; but νηδύς, by poetic license, is shortened. And υ, when lengthened in the nominative, tends to shorten the other cases, not only in πῦρ πυρός, but also in ἰχθύος, δρυός, ἰσχύος, ἰλύος. But in «ἰλύος» (Φ 318) the υ is lengthened because of the metre.
Nouns in -υς that are barytone, whether feminine or masculine, are shortened: γένυς, πίτυς, χέλυς, γῆρυς, ἀτράφαξυς, Πόλτυς, βότρυς, Ἕρπυς, Ἅλυς, ἥμισυς, πέλεκυς, Ῥαδάμανθυς.
Adjectives in -υς that are oxytone are shortened: πολύς, ἠΰς, ἡδύς, βραδύς.
All compounds in -υς have υ shortened and are proparoxytone: σύνοφρυς, λεύκοφρυς, κάλλιχθυς, δίβραχυς.
Masculine oxytone disyllables in -ος, pure, with a long/short penult, lengthen it, e.g. ναός, λαός, κριός, ἰός, except βιός.
Pure masculine disyllables in -ος, if they have α in the penult, lengthen it: ναός, λαός. δάος is neuter. σάος is noted as exceptional.
Disyllabic oxytones ending in -λος, whenever they have a long/short vowel before the end, have it either shortened or lengthened, either by itself or made long by a consonant. And those made long by consonants are such as κυλλός, μαλλός, θαλλός; while those by themselves are such as ψιλός, χυλός, δαλός, βαλός; likewise βαθμός both in tragedy and in comedy. Therefore καλός too ought either to be supported by a consonant or to be lengthened of itself. Sound, then, is the lengthening in the poet.
Derivatives in -ιμος of more than two syllables have ι shortened: κύδιμος, ὠφέλιμος, ὤκιμος. But ἄτιμος, which lengthens ι, is a compound. In this way βούλιμος too is held to be lengthened in the second syllable, since the noun is a compound: for it stands for “the great hunger.” And ἴφθιμος too lengthens the ι before the end.
Pure disyllables in -μος having υ lengthen it and are oxytone: χυμός, θυμός, δρυμός, ῥυμός. But if it is of more than two syllables, they wish both to be proparoxytone and to shorten υ, unless…