The act of involving or infolding.

The state of being entangled or involved; complication;
entanglement.

That in which anything is involved, folded, or wrapped;
envelope.

The insertion of one or more clauses between the
subject and the verb, in a way that involves or complicates the
construction.

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.

The return of an enlarged part or organ to its normal
size, as of the uterus after pregnancy.