Nouns

(n)involutionreduction in size of an organ or part (as in the return of the uterus to normal size after childbirth)
(n)involutiona long and intricate and complicated grammatical construction
(n)elaborateness, elaboration, intricacy, involutionmarked by elaborately complex detail
(n)engagement, participation, involvement, involutionthe act of sharing in the activities of a group“the teacher tried to increase his students' engagement in class activities”
(n)exponentiation, involutionthe process of raising a quantity to some assigned power
(n)involution, enfoldingthe action of enfolding something