INVOLUTION

noun Etymology: Latin ~-, involutio, from involvere Date: circa 1611 1. a. the act or an instance of enfolding or entangling ; involvement, an involved grammatical construction usually characterized by the insertion of clauses between the subject and predicate, complexity , intricacy , exponentiation , 3. an inward curvature or penetration, the formation of a gastrula by ingrowth of cells formed at the dorsal lip, a shrinking or return to a former size, the regressive alterations of a body or its parts characteristic of the aging process , ~al adjective