involute

American Heritage® Dictionary of the English Language, Fourth Edition

1. adj. Intricate; complex.
2. adj. Botany Having the margins rolled inward.
3. adj. Botany Having whorls that obscure the axis or other volutions, as the shell of a cowrie.
4. v. To curl inward.
5. v. To return to a normal or former condition.
6. n. The curve traced by a point on a taut, inextensible string as it unwinds from another curve.

Century Dictionary and Cyclopedia

1. Rolled up; wrapped up. Specifically— In botany, rolled inward from the edge or edges: said of leaves in vernation, of the petals of flowers in estivation, and of the margin of the cup in the Discomycetes, etc. Also involutive.
2. Involved; confusedly mingled.
3. n. That which is involved.
4. n. In geometry, the curve traced by any point of a flexible and inextensible string when the latter is unwrapped, under tension, from a given curve; or, in other words, the locus of a point in a right line which rolls, without sliding, over a given curve. The curve by unwrapping which a series of involutes is obtained is said to be their common evolute, and auy two involutes of a curve constitute a pair of parallel curves, their corresponding tangents being parallel, and their corresponding points, situated on the same normal, being at a constant distance from one another.
5. Noting a form of tooth-profile, used in gearing, traced by a point at the end of a tangent as it is unwrapped from a base-circle. The base-circle is the circle at the root of the teeth. All involute teeth of the same circular pitch will work together. They are much used in cases where the distance between the centers of the two shafts has to be slightly variable.
6. To return to a normal condition.

Wiktionary

1. adj. formal Difficult to understand; complicated.
2. adj. botany Having the edges rolled with the adaxial side outward.
3. adj. biology, of shells Having a complex pattern of coils.
4. adj. biology Turned inward at the margin, like the exterior lip of the Cyprea.
5. adj. biology Rolled inward spirally.
6. v. To roll or curl inwards.
7. n. geometry A curve that cuts all tangents of another curve at right angles; traced by a point on a string that unwinds from a curved object.

GNU Webster's 1913

1. adj. (Bot.) Rolled inward from the edges; -- said of leaves in vernation, or of the petals of flowers in æstivation.
2. adj. Turned inward at the margin, as the exterior lip of the Cyprea.
3. adj. Rolled inward spirally.
4. n. (Geom.) A curve traced by the end of a string wound upon another curve, or unwound from it; -- called also evolvent. See evolute.

WordNet 3.0

1. adj. (of some shells) closely coiled so that the axis is obscured
2. adj. especially of petals or leaves in bud; having margins rolled inward