# capillary

/ˈkæpəˌɫɛɹi/ (US) · /kˈæpɪləɹi/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/capillary
Updated: 2026-05-19

## Definition

a tiny blood vessel that connects the smallest arteries to the smallest veins. It is so thin that blood cells can only pass through one at a time.

For teachers: a microscopic blood vessel that connects arterioles to venules, facilitating the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues.

## Examples

- The capillary network allows oxygen to reach every cell in the body.
- In the lungs, oxygen diffuses from the air sacs into the blood through the thin walls of the capillaries.
- The dense arrangement of capillaries in the kidneys is essential for the efficient filtration of blood and the reabsorption of vital nutrients back into the circulatory system.

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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.