Greek discussion of place-names and words ending in -υς, with rules about accentuation and contraction: compounds with contracted υ are proparoxytone; feminine -υς extend the υ and are oxytone; diminutives and forms often take circumflex, with listed exceptions (ὀφρῦς, ὀσφῦς, ἰχθῦς); poetic contractions cited (Καλλιμάχῳ, Εὐριπίδῃ).
Πάτρασυς πόλις Ποντικὴ ὡς Ἑκαταῖος Ἀσίᾳ. Πίναμυς πόλις Αἰγύπτου. Τὰ εἰς 'υς' πάντα σύνθετα συνεσταλμένον ἔχοντα τὸ 'υ' προπαροξύνεται, σύνοφρυς, λεύκοφρυς καὶ Λεύκοφρυς· οὕτω γὰρ ἐκαλεῖτο ἡ Τένεδος, κάλλιχθυς, δίβραχυς, ἀρσενόθηλυς, δίπηχυς, ἔπηλυς, νέηλυς. Τὰ εἰς 'υς' θηλυκὰ ἐκτείνοντα τὸ 'υ' ὀξύνεται, πληθύς, ἐδητύς, ὀϊζύς, ἐρινύς, ἰξύς ἡ ῥάχις, ἰσχύς, ἰλύς, κλιτύς, ἀλητύς, ῥυστακύς, ἀγλύς σημειῶδες κατὰ κλίσιν· διὰ γὰρ τοῦ 'θος' ἐκλίθη, οὐ διὰ καθαροῦ τοῦ 'ος'. τὸ δὲ νηδύς ποιητικῇ ἀδείᾳ συστέλλεται ὡς παρὰ Καλλιμάχῳ (h. Dian. 160) «ἔτι οἱ πάρα νηδὺς ἐκείνη» καὶ παρ´ Εὐριπίδῃ ἐν Ἀνδρομάχῃ ( 356) «καὶ νηδὺν ἐξαμβλοῦμεν ὡς αὐτὸς λέγει». σεσημείωται ἐν τοῖς θηλυκοῖς τὸ ὀφρῦς καὶ ὀσφῦς ἡ ῥάχις περισπώμενα. Τὰ εἰς 'υς' ὑποκοριστικὰ περισπῶνται, καμμῦς, κλαυσῦς, λαρδῦς, Διονῦς, ἀπφῦς. Εὑρίσκεται οὖν τὰ εἰς 'υς' ὑπὲρ μίαν συλλαβὴν περισπώμενα ὑποκοριστικὰ πάντα πλὴν τοῦ ὀσφῦς καὶ ὀφρῦς καὶ ἰχθῦς. τὸ δὲ ἰξύς, εἰ καὶ ἐν τῷ ὀνοματικῷ παρεθέμεθα ὡς περισπώμενον ἀλόγως ὥσπερ τὸ δρῦς καὶ μῦς καὶ σῦς, ἀλλ´ οὖν ὀξύνεται.
Patrasys, a Pontic city, as Hecataeus says in his Asia. Pinamys, a city of Egypt. All compounds in -υς, having the υ shortened, are accented on the antepenult: σύνοφρυς, λεύκοφρυς, and Λεύκοφρυς—for thus Tenedos was called—κάλλιχθυς, δίβραχυς, ἀρσενόθηλυς, δίπηχυς, ἔπηλυς, νέηλυς. Feminines in -υς that lengthen the υ are accented with an acute: πληθύς, ἐδητύς, ὀϊζύς, ἐρινύς, ἰξύς ‘the spine’, ἰσχύς, ἰλύς, κλιτύς, ἀλητύς, ῥυστακύς, ἀγλύς—remarkable in its inflection; for it is declined with -θος, not with a pure -ος. But νηδύς, by poetic license, is shortened, as in Callimachus (h. Dian. 160) “ἔτι οἱ πάρα νηδὺς ἐκείνη” and in Euripides in the Andromache (356) “καὶ νηδὺν ἐξαμβλοῦμεν ὡς αὐτὸς λέγει”. Noted among the feminines are ὀφρῦς and ὀσφῦς ‘the spine’, with circumflex. Diminutives in -υς take a circumflex: καμμῦς, κλαυσῦς, λαρδῦς, Διονῦς, ἀπφῦς. It is found, then, that all diminutives in -υς of more than one syllable take a circumflex, except ὀσφῦς and ὀφρῦς and ἰχθῦς. But ἰξύς, although in the nominative we set it down as circumflexed, irrationally, like δρῦς and μῦς and σῦς, is nevertheless accented with an acute.