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Webster 1913 Edition

Noun.

[L.

evolutus

unrolled, p. p. of

evolvere

. See

(Geom.)

A curve from which another curve, called the

involute

or evolvent, is described by the end of a thread gradually wound upon the former, or unwound from it. See

. It is the locus of the centers of all the circles which are osculatory to the given curve or evolvent.

☞ Any curve may be an evolute, the term being applied to it only in its relation to the involute.

Noun.

An original curve from which another curve is described; the origin of the evolent.