Coined by Ruysch from Greek epi- 'upon' + thēlē 'nipple,' originally for the membrane covering the lip, then generalized to all lining tissues.
The thin tissue forming the outer layer of the body's surface and lining internal organs, cavities, and glands.
Coined by Dutch anatomist Frederik Ruysch from Greek epi- 'upon' + thēlē 'nipple.' Ruysch first used it to describe the thin membrane covering the lip's surface, which he thought resembled the skin covering a nipple. The term was later generalized to all surface-lining tissues. Key roots