[flex.ion] n [L flexion-, flexio, fr. flectere] (1615) 1: the act of flexing or bending
2: a part bent: bend
3: inflection 3
4. a: a bending movement around a joint in a limb (as the knee or elbow) that decreases the angle between the bones of the limb at the joint--compare extension 3b b: a forward raising of the arm or leg by a movement at the shoulder or hip joint