evolute

American  

[ev-uh-loot, ee-vuh-] / ˈɛv əˌlut, ˈi və- /

noun

Geometry.

1. the locus of the centers of curvature of, or the envelope of the normals to, another curve.

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evolute British  

/ 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

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adjective

1. biology having the margins rolled outwards

Etymology

Origin of evolute

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

Example Sentences

Both of these liquids have specific pericosities given by P = 2.5C.n^6-7 where n is the diathetical evolute of retrograde temperature phase disposition and C is Cholmondeley's annular grillage coefficient.

From Time Magazine Archive

If the second medium be more highly refractive than the first, the secondary caustic is a hyperbola having the same focus and centre as before, and the caustic is the evolute of this curve.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" by Various

These names are given to the curves because the end of a stretched thread unwound from the evolute will describe the involute.

From The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar by Various

The evolute of a curve is the curve which is the envelope of all its normals or the locus of all its centres of curvature.

From The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar by Various

Secondary caustics are orthotomic curves having the reflected or refracted rays as normals, and consequently the proper caustic curve, being the envelope of the normals, is their evolute.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" by Various