[in.vo.lu.tion] n [L involution-, involutio, fr. involvere] (ca. 1611) 1 a (1): the act or an instance of enfolding or entangling: involvement (2): an involved grammatical construction usu. characterized by the insertion of clauses between the subject and predicate b: complexity, intricacy
2: exponentiation 3 a: an inward curvature or penetration b: the formation of a gastrula by ingrowth of cells formed at the dorsal lip
4: a shrinking or return to a former size
5: the regressive alterations of a body or its parts characteristic of the aging process; specif: decline marked by a decrease of bodily vigor and in women by menopause -- in.vo.lu.tion.al adj