evolute

UK: /ˈɛvəˌluːt/ US: (ev′ə lo̅o̅t′ or, esp. Brit.,, ē′və-)

WordReference Random House Unabridged Dictionary of American English © 2026

ev•o•lute  (ev′ə lo̅o̅t′ or, esp. Brit.,, ē′və-), n. [Geom.]

1. Mathematics the locus of the centers of curvature of, or the envelope of the normals to, another curve. Cf. involute (def. 5).

• Latin ēvolūtus (past participle of ēvolvere to roll out, unfold, evolve)
• 1720–30

Collins Concise English Dictionary © HarperCollins Publishers::

evolute / ˈɛvəˌluːt/ noun

1. a geometric curve that describes the locus of the centres of curvature of another curve (the involute). The tangents to the evolute are at right angles to the involute

adjective

1. having the margins rolled outwards

Etymology: 19th Century: from Latin ēvolūtus unrolled, from ēvolvere to roll out, evolve