Defn: 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 Involute. It is the locus of the centers of all the circles which are osculatory to the given curve or evolvent.
Note: Any curve may be an evolute, the term being applied to it only in its relation to the involute.
EVOLUTILITY
Ev`o*lu*til"i*ty, n. Etym: [See Evolution.] (Biol.)
Defn: The faculty possessed by all substances capable of self- nourishment of manifesting the nutritive acts by changes of form, of volume, or of structure. Syd. Soc. Lex.
EVOLUTION Ev`o*lu"tion, n. Etym: [L. evolutio an unrolling: cf. F. évolution evolution. See Evolve.]
1. The act of unfolding or unrolling; hence, in the process of growth; development; as, the evolution of a flower from a bud, or an animal from the egg.
2. A series of things unrolled or unfolded. "The whole evolution of ages." Dr. H. More.
3. (Geom.)
Defn: The formation of an involute by unwrapping a thread from a curve as an evolute. Hutton.
4. (Arith. & Alg.)