involution

The act of involving.

The state of being involved.

Intricacy; complexity.

Something, such as a long grammatical construction, that is intricate or complex.

An operation, such as negation, which, when applied to itself, returns the original number.

The ingrowth and curling inward of a group of cells, as in the formation of a gastrula from a blastula.

A decrease in size of an organ, as of the uterus following childbirth.

A progressive decline or degeneration of normal physiological functioning occurring as a result of the aging process.