flexion

noun

flex·​ion ˈflek-shən 

1

: the act of flexing or bending

2

: a part bent : bend

3

: inflection sense 2

4

a

: a bending movement around a joint in a limb (such as the knee or elbow) that decreases the angle between the bones of the limb at the joint compare extension sense 3b

b

: a forward raising of the arm or leg by a movement at the shoulder or hip joint

Examples of flexion in a Sentence

Recent Examples on the Web

At the end of the trial, the exercise group showed greater improvements in the side-step and sitting trunk flexion tests than the control group. —Lindsey Leake, NBC news, 29 Apr. 2026

The team enabled real-time perception of both flexion and side-to-side movement in delicate manipulation tasks. —Prabhat Ranjan Mishra, Interesting Engineering, 3 Apr. 2026

Ankle flexion, ability to get in and out (of breaks)? —Jourdan Rodrigue, New York Times, 5 Mar. 2026

And along the outer forearm is the brachioradialis, which assists with elbow flexion, especially when your hand is in a neutral, thumbs-up position. —Daryl Austin, USA Today, 19 Feb. 2026

Word History

Etymology

borrowed from Latin flexiōn-, flexiō "act of bending or curving," from flectere "to cause to go in a different direction, bend, curve" (of uncertain origin) + -tiōn-, -tiō, suffix of verbal action

First Known Use

1615, in the meaning defined at sense 1

Rhymes for flexion

• lection
• rection
• section
• abjection
• advection
• affection
• bijection
• bisection
• collection
• complexion
• confection
• connection

Kids Definition

flexion

noun

flex·​ion ˈflek-shən 

: a bending movement around a joint (as the knee or elbow) in an arm or leg that lessens the angle between bones of the arm or leg at the joint

also : the resulting state

Medical Definition

flexion

noun

flex·​ion

variants also flection

ˈflek-shən 

1

: 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 sense 2

2

: a forward raising of the arm or leg by a movement at the shoulder or hip joint