flexió

Flexió is a term used in several languages to denote the act or result of bending or changing form. It derives from the Latin flexio, from flectere, to bend, and the meaning varies by field.

In anatomy, flexió (often rendered as flexion in English) describes the movement that decreases the angle between two segments at a joint, bringing parts closer together. Common examples include elbow flexion and knee flexion. The opposite movement is extension.

In linguistics, flexió denotes the inflection of a word—the modification of its form to express grammatical categories such as tense, mood, number, person, case, or gender. Inflectional changes can involve affixes, internal vowel changes, or stem modifications and are a central aspect of morphology. In some languages, flexió is the standard term for inflection.

In materials science and engineering, flexió refers to bending under load. Flexion tests assess properties like stiffness, strength, and elasticity, often using beams or wires subjected to bending moments. In botany, the term can describe natural bending of stems or leaves.

Etymology: from Latin flexio, from flectere—to bend. The concept appears across disciplines, reflecting a common geometric idea of changing an angle or form.

See also: Flexion, Inflection, Bending, Elasticity.