Intussusception

intussusception \ˌin-tə-sə-ˈsep-shən\ noun: a drawing in of something from without, as 1. invagination (especially the slipping of a length of intestine into an adjacent portion usually producing obstruction), 2. the assimilation of new material and its dispersal among preexistent matter

Etymology: Latin intus within + susception-, susceptio action of undertaking, from suscipere to take up

These two definitions are so different from one another that you and your conversational partners had better be on the same page when using intussusception.