1707, literally "a taking in," from Latin intus "within" (see ento-) + susceptionem "a taking up" (see susceptible).
intussusception in·tus·sus·cep·tion (ĭn'tə-sə-sěp'shən)n.
Invagination, especially an infolding of one part of the intestine into another.
Assimilation of new substances into the existing components of living tissue. Also called introsusception.