any regular recurring motion (πᾶς ῥ. ὡρισμένῃ μετρεῖται κινήσει Arist. Pr. 882b2):
measured motion, time, whether in sound or motion, Democr. 15c; = ἡ τῆς κινήσεως τάξις, Pl. Lg. 665a, cf. 672e; ὁ ῥ. ἐκ τοῦ ταχέος καὶ βραδέος, ἐκ διενηνεγμένων πρότερον, ὕστερον δὲ ὁμολογησάντων γέγονε Id. Smp. 187b, cf. Suid. s.v.; rhythm, opp. μέτρον and ἁρμονία, Ar. Nu. 638 sq., Pl. R. 397b, 398d, 601a, Arist. Rh. 1403b31; λόγοι μετὰ μουσικῆς καὶ ῥυθμῶν πεποιημένοι Isoc. 15.46; of Prose rhythm, Arist. Rh. 1408b29, D.H. Comp. 17: defined by Aristox. Rhyth. 1, Aristid.Quint. 1.13.
special phrases: ἐν ῥυθμῷ in time, of dancing, marching, etc., βαίνειν ἐν ῥ. Pl. Lg. 670b, cf. X. An. 5.4.14; ὀρχεῖσθαι Id. Cyr. 1.3.10; ἐν τῷ ῥ. ἀναπνεῖν respire regularly, Arist. Pr. 882b1; so σωζόμενος ῥ. A. Ch. 797 (lyr.); μετὰ ῥυθμοῦ βαίνοντες Th. 5.70; ῥυθμὸν χορείας ὑπάγειν keep time, Ar. Th. 956 (lyr.); θάττονα ῥυθμὸν ἐπάγειν play in quicker time, X. Smp. 2.22; πυρριχίῳ δρόμῳ καὶ ῥυθμῷ Hdn. 4.2.9, cf. Plb. 4.20.6: pl., paces, Alcid. Soph. 17.
measure, proportion or symmetry of parts, at rest as well as in motion, κατὰ τὸν αὐτὸν ῥ. Pl. Lg. 728e.
generally, proportion, arrangement, order, ῥυθμῷ τινι E. Cyc. 398 (codd., but θʼ ἑνὶ is prob.); οὐκ ἀπὸ ῥυσμοῦ εἰκάζω not without reason, Call. Epigr. 44.5.
state or condition of anything, temper, disposition, Thgn. 964 (coupled with ὀργή and τρόπος) ; οἷος ῥυσμὸς ἀνθρώπους ἔχει Archil. 66.7; ὅσοι χθονίους ἔχουσι ῥυσμοὺς καὶ χαλεπούς Anacr. 74; μένει . . χρῆμʼ οὐδὲν ἐν ταὐτῷ ῥ. Eup. 356.
form, shape of a thing, Democr. 5i; identified by Arist. with σχῆμα, Metaph. 985b16, 1042b14; μετέβαλον τὸν ῥ. τῶν γραμμάτων changed the form or shape of the letters, Hdt. 5.58; of Chian boots, Hp. Art. 62; of the shape of a cup, Alex. 59; of a breastplate, X. Mem. 3.10.10; [τοῦ θυσιαστηρίου] LXX 4 Ki. 16.10; Αὐτονόας ῥ. ωὑτός Theoc. 26.23; so of the natural features of a country, D.P. 271, 620; structure of a substance, κεγχροειδὲς τῷ ῥ., τῷ ῥ. σπογγῶδες, Dsc. 5.77,118.
manner, fashion of a thing, Ἕλλην ῥ. πέπλων E. Heracl. 130; τίνι ῥ. φόνου; by what kind of slaughter? Id. El. 772, cf. Supp. 94; ἐν τριγώνοις ῥυθμοῖς triangular-wise, A. Fr. 78. [ῠ by nature, A. Ch. 797 (lyr.), E. Supp. 94, etc.; ῡ by position in Thgn. 964, etc.]