Definition of evolute in English:


(also evolute curve)


  • A curve which is the locus of the centres of curvature of another curve (its involute).

    • ‘Of course the evolute of an involute of a circle is a circle.’
    • ‘On 22 January 1769 Monge wrote to Bossut explaining that he was writing a work on the evolutes of curves of double curvature.’
    • ‘He gives propositions determining the centre of curvature which lead immediately to the Cartesian equation of the evolute.’
    • ‘He defines evolutes and involutes of curves and, after giving some elementary properties, finds the evolutes of the cycloid and of the parabola.’
    • ‘Hence a curve has a unique evolute but infinitely many involutes.’


Zoology Botany
  • Rolled outwards at the edges.

    ‘an evolute shell’
    • ‘The general shell characters are the evolute coiling and the median keel that is always higher than the lateral ones.’
    • ‘These younger descendants differ from Goniatites in their evolute inner whorls, their wider external lobe, and their higher median saddle.’
    • ‘It essentially separates early (higher scores) and later (lower scores) representatives of the species, which tended to develop evolute coiling through geologic time.’
    • ‘Most clymeniids and contemporary goniatitids (with both evolute and involute shells) declined before the last anoxic episode, known as the Hangenberg event, which was followed by a major regression.’
    • ‘The second lineage contained A. nitida, which became more involute and axially compressed on the umbilical side, and its first descendant, A. mckannai, which developed evolute coiling and a moderately wide umbilicus.’


Mid 18th century: from Latin evolutus, past participle of evolvere ‘roll out’ (see evolve).