Definitions

1. noun

A layer of cells forming the lining or covering of a gland, organ, or other body part, especially the skin, respiratory tract, and gastrointestinal tract.

“The epithelium of the skin acts as a barrier against external factors.”

2. noun

The lining or covering of a gland or organ, especially the epithelial lining of a gland or organ.

“The epithelium of the kidney filters waste and excess fluids from the blood.”