■ noun
1》 Physiology the shrinkage of an organ in old age or when inactive.
2》 Mathematics a function, transformation, or operator that is equal to its inverse.
3》 formal the process or state of complication.
Derivatives
~al adjective
Origin
ME (in the sense '(part) curling inwards'): from L. involutio(n-) , from involvere (see involve ).