Convolution and Involution

convolution

(n.) An irregular, tortuous folding of an organ or part; as, the convolutions of the intestines; the cerebral convolutions. See Brain.
(n.) The state of being rolled upon itself or rolled or doubled together; a tortuous or sinuous winding or fold, as of something rolled or folded upon itself.
(n.) The act of rolling anything upon itself or one thing upon another; a winding motion.

Webster's Revised Unabridged Dictionary

involution

Reduction in size of an organ or part (as in the return of the uterus to normal size after childbirth. )
A long and intricate and complicated grammatical construction.
Marked by elaborately complex detail.
- synonyms: elaborateness, elaboration, intricacy
The act of sharing in the activities of a group.
- usage: "the teacher tried to increase his students' engagement in class activities"
- synonyms: engagement, participation, involvement
The process of raising a quantity to some assigned power.
- synonyms: exponentiation
The action of enfolding something.
- synonyms: enfolding

(n.) The state of being entangled or involved; complication; entanglement.
(n.) The act of involving or infolding.
(n.) The return of an enlarged part or organ to its normal size, as of the uterus after pregnancy.
(n.) The relation which exists between three or more sets of points, a.a', b.b', c.c', so related to a point O on the line, that the product Oa.Oa' = Ob.Ob' = Oc.Oc' is constant. Sets of lines or surfaces possessing corresponding properties may be in involution.
(n.) That in which anything is involved, folded or wrapped; envelope.
(n.) The act or process of raising a quantity to any power assigned; the multiplication of a quantity into itself a given number of times; -- the reverse of evolution.
(n.) The insertion of one or more clauses between the subject and the verb, in a way that involves or complicates the construction.

Webster's Revised Unabridged Dictionary