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

The pleasing effect of the design at Seventh and Locust streets is largely due to appropriate use of the evolute spiral band.

From The Colonial Architecture of Philadelphia by Cousins, Frank

The intrinsic equation is s = 4a sin ψ, and the equation to the evolute is s = 4a cos ψ, which proves the evolute to be a similar cycloid placed as in fig.

From Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" by Various

The thread has a marker, E, so that when the thread is wound on the spool the marker E makes the evolute line A. 163.

From Carpentry for Boys In a Simple Language, Including Chapters on Drawing, Laying Out Work, Designing and Architecture With 250 Original Illustrations by Zerbe, James Slough

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