Is it ensure, insure, or assure?
1721, from Latin intestinum caecum "blind gut," from neuter of caecus "blind, hidden," from Proto-Italic *kaiko-, from PIE *kehi-ko- "one-eyed," cognate with Old Irish ca'ech "one-eyed," coeg "empty," Welsh coeg-dall, Old Cornish cuic "one-eyed;" Gothic haihs "one-eyed, blind." So called for being prolonged into a cul-de-sac.
caecum cae·cum (sē'kəm)
Variant of cecum.
pouch or large tubelike structure in the lower abdominal cavity that receives undigested food material from the small intestine and is considered the first region of the large intestine. It is separated from the ileum (the final portion of the small intestine) by the ileocecal valve (also called Bauhin valve), which limits the rate of food passage into the cecum and may help prevent material from returning to the small intestine.