# epithelium

/ˌɛpɪˈθiɫjəm/ (US) · /ˌɛpɪθˈiːliəm/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/epithelium
Updated: 2026-05-28

## Definition

a thin layer of cells that covers the outside of your body and lines your organs and cavities. It acts as a protective barrier and helps your body absorb things.

For teachers: a layer of tissue that covers all internal and external surfaces of the body, including the skin and the lining of organs. It serves as a protective barrier and facilitates the absorption and secretion of substances.

## Examples

- The skin is the largest organ in the body and is made of epithelium.
- The lining of the small intestine is a specialized epithelium designed to maximize the absorption of nutrients from food.
- Damage to the respiratory epithelium can impair the body's ability to filter out airborne pathogens, leading to increased susceptibility to infections and chronic inflammation.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.