εὐτονία

A. tension, vigour, D.S. 5.39; σκελῶν ib.34: esp. in Stoic philos. (cf. τόνος), Chrysipp.Stoic. 2.146, etc.; ὁ ἐν τῇ ψυχῇ τόνος λέγεται ὡς εὐ. καὶ ἀτονία ib. 3.123, cf. Phld. Ir. p.69 W.; εὐ. ψυχῆς, of courage, Stoic. 3.66, cf. 73: generally, vigour of character, Plu. Phoc. 3, 2.456f, BGU 786ii 1 (ii A.D.); also, vigour of style, D.H. Vett.Cens. 2.3, Hermog. Id. 1.11, Aps.p.282 H.

b. Medic., tension, Ruf. Sat.Gon. 46 (pl.); also μαλθακὴ εὐ. gentle force, Hp. Ep. 15.

c. elasticity, Ph. Bel. 71.33.