capillary

1 of 2

adjective

cap·​il·​lary ˈka-pə-ˌler-ē 

-ˌle-rē,

 British usually  kə-ˈpi-lə-rē

1

a

: resembling a hair especially in slender elongated form

capillary leaves

b

: having a very small bore

a capillary tube

2

: involving, held by, or resulting from surface tension

capillary water in the soil

3

: of or relating to capillaries or capillarity

capillary

2 of 2

noun

plural capillaries

1

: a minute thin-walled vessel of the body

especially : any of the smallest blood vessels connecting arterioles with venules and forming networks throughout the body

2

: a tube (as of glass) having a very small bore

Examples of capillary in a Sentence

Recent Examples on the Web

Adjective

By measuring how quickly this light fades (that is, its phosphorescence lifetime), the researchers could calculate pO2 at the capillary level. —New Atlas, 2 Oct. 2025

These vampiric bugs use needle-like mouthpieces to locate a capillary and inject saliva containing anesthetics and anticoagulants into its host allowing blood to flow freely into their stomachs for several minutes. —Katie Nixon, Nashville Tennessean, 23 Sep. 2025

Noun

The arteries end at the capillaries. —Bryant Stamford, Louisville Courier Journal, 2 Oct. 2025

Drinking alcohol also weakens collagen and elastin (the stuff that keeps skin bouncy and firm) and can contribute to volume loss and broken capillaries—the tiny red veins that pop up around the nose and cheeks. —Donna Francis, Allure, 25 Aug. 2025

Word History

Etymology

Adjective

French or Latin; French capillaire, from Latin capillaris, from capillus hair

First Known Use

Adjective

14th century, in the meaning defined at sense 1a

Noun

1667, in the meaning defined at sense 1

Phrases Containing capillary

• capillary attraction
• capillary electrophoresis

Rhymes for capillary

• accessary
• adversary
• ancillary
• arbitrary
• aviary
• axillary
• beriberi
• breviary
• budgetary
• catenary
• cautionary
• cemetery

Kids Definition

capillary

1 of 2 adjective

cap·​il·​lary ˈkap-ə-ˌler-ē 

1

: having a long slender form and a very small inner diameter

a capillary tube

2

: of or relating to capillaries or capillarity

capillary

2 of 2 noun

plural capillaries

: a capillary tube

especially : any of the tiny blood vessels connecting the small arteries and veins

Medical Definition

capillary

1 of 2 adjective

cap·​il·​lary

ˈkap-ə-ˌler-ē, British usually kə-ˈpil-ə-rē

1

a

: resembling a hair especially in slender elongated form

b

: having a very small bore

a capillary tube

2

: involving, held by, or resulting from surface tension

3

: of or relating to capillaries or capillarity

capillary

2 of 2 noun

plural capillaries

1

: a minute thin-walled vessel of the body

especially : any of the smallest blood vessels connecting arterioles with venules and forming networks throughout the body

2

: a capillary tube