Lewis & Short

flexĭo, ōnis, f. [flecto], a bending, swaying, turning; a bend, turn, curve (rare but class.).

  1. I. Lit.: trunco toto se ipse moderans et virili laterum flexione, Cic. Or. 18, 59; id. de Or. 3, 59, 220.
  2. II. Trop.
    1. A. In gen.: quae deverticula flexionesque quaesisti! i. e. turnings, windings, Cic. Pis. 22, 53.
    2. B. In partic., of the voice, a modulation, inflection, change: est in dicendo etiam quidam cantus obscurior … quem significat Demosthenes et Aeschines, cum alter alteri obicit vocis flexiones, Cic. Or. 18, 57: delicatiores in cantu, id. de Or. 3, 25, 98: ut cervices oculosque pariter cum modorum flexionibus torquent, id. Leg. 2, 15, 39.