Well, it appears that maybe I don't know what invagination is, but then again, maybe I do.

Don't recall where I came across the word, but wherever it was, it was so deeply mired in anatomical gobbledegook that I was clueless not only about what it was, but even if it was a verb, noun, or act of congress. Then I noticed what word was in the middle, and thought 'Could it mean some kind of pouching or something like that?', and promptly started looking down a series of references in Google, none of which helped me even get an image. Then I came across a reference to intussusception at www.vulgaris-medical.com, and -- even though I can't say it without a running jump -- I know what that word means, kind of a pouch fold in the intestines -- so, maybe I do.

I enjoy anatomical words and medical articles. I just don't always understand them.