involution

英 [ɪnvə'l(j)uːʃ(ə)n] 美[,ɪnvə'lʊʃən]

• n. [生物] 退化；纠缠（的事物）；乘方

1. reduction in size of an organ or part (as in the return of the uterus to normal size after childbirth)

2. a long and intricate and complicated grammatical construction

3. marked by elaborately complex detail

4. the act of sharing in the activities of a group;

"the teacher tried to increase his students' engagement in class activities"

5. the process of raising a quantity to some assigned power

6. the action of enfolding something