flexion Syllabification: (flex·ion)Pronunciation: /ˈflekSHən/ (also flection)Definition of flexion noun the action of bending or the condition of being bent, especially the bending of a limb or joint:flexion of the fingers these protozoans can move by body flexionsOrigin: early 17th century: from Latin flexio(n-), from flectere 'to bend'flexion in other Oxford dictionaries Definition of flexion in the British & World English dictionary