Definition of involute in English:

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Pronunciation: /ˈɪnvəl(j)uːt/


1 formal Involved or intricate: the art novel has grown increasingly involute
2 technical Curled spirally.
2.1 Zoology (Of a shell) having the whorls wound closely round the axis.
Example sentences
  • Most contemporary goniatitids had an involute shell with compressed whorls.
  • In the Anaspidea there is a tendency for parapodia to enlarge and, together with the mantle, to enclose the fragile shell (with increasingly reduced and involute spire).
  • Although no equatorial sections were recovered, the present specimens exhibit a likely involute initial stage followed by biserial, uncoiled later stage in which chambers are more flattened.
2.2 Botany (Of a leaf or the cap of a fungus) rolled inwards at the edges.
Example sentences
  • They were found to comprise at least three different traits: involute leaves, early flowering, and Apetala flowers.
  • Distinguishing characteristics are fully double, involute florets that are narrow and pointed.
  • This mutant displayed involute leaves and early flowering, although less than clf and icu2 mutants (20 days after sowing).


The locus of a point considered as the end of a taut string being unwound from a given curve in the plane of that curve. Compare with evolute.
Example sentences
  • Since normals to a straight line never intersect and tangents coincide with the curve, evolutes, involutes and pedal curves are not too interesting.
  • 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.


Mid 17th century: from Latin involutus, past participle of involvere (see involve).

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