The act of involving. The state of being involved.
Intricacy; complexity.
Something, such as a long grammatical construction, that is intricate or complex.
Mathematics An operation, such as negation, which, when applied to itself, returns the original number.
Embryology The ingrowth and curling inward of a group of cells, as in the formation of a gastrula from a blastula.
Medicine 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.