Pronunciation: (in"tus-su-sep'shun), [key]
1. a taking within.
2. Biol.growth of a cell wall by the deposition of new particles among the existing particles of the wall. Cf. apposition (def. 4).
3. Also called invagination. Pathol.the slipping of one part within another, as of the intestine.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.