capillary

Everyday

1. A capillary is the thinnest kind of blood vessel in the body, finer than a hair, that connects arteries and veins. tree →
2. A capillary is any very thin tube. tree →
3. Capillary action is the way water moves up through thin tubes or tiny gaps, like in paper or plants. tree →

In the lessons

In science lessons about the body blood flows from the heart in arteries, through capillaries where oxygen and food pass into the body's cells, and back in veins. In experiments with paper towels, celery and food colouring, pupils see water climb by capillary action, which helps water rise in plants.

Examples

• Oxygen passes from the capillaries into your cells. tree →
• Capillaries are thinner than a hair. tree →
• Water climbed up the paper towel by capillary action. tree →
• The celery turned blue because coloured water rose up its tubes. tree →
• A bruise forms when tiny capillaries break under the skin. tree →
• Blood goes: arteries, capillaries, veins. tree →

Note

Countable: capillaries (y → ies). Pronounced «ka-PIL-a-ree» in the UK, «KAP-i-lair-ee» in the US. Three kinds of blood vessel: arteries (away from heart), veins (back to heart), capillaries (tiny links).