The definition of a capillary is a small blood vessel that is part of the network of the small arteries and small veins, or an extremely thin tube through which nothing thicker than a human hair can pass.
A tiny blood vessel in your body that connects your smallest arteries (your arterioles) to your smallest veins (your venules) is an example of a capillary.
A close up of an eye showing the capillaries.
capillary definition by Webster's New World
of or like a hair, esp. in being very slender
having a very small bore
in or of capillaries
Origin: Classical Latin capillaris ; from capillus, hair
capillary definition by American Heritage Dictionary
Relating to or resembling a hair; fine and slender.
Having a very small internal diameter: a capillary tube.
Anatomy Of or relating to the capillaries.
Physics Of or relating to capillarity.
Anatomy One of the minute blood vessels that connect arterioles and venules. These blood vessels form an intricate network throughout the body for the interchange of various substances, such as oxygen and carbon dioxide, between blood and tissue cells.
A tube with a very small internal diameter.
Origin: From Latin capillāris, from capillus, hair.
Any of the tiny blood vessels that connect the smallest arteries (arterioles) to the smallest veins (venules). Capillaries form a network throughout the body for the exchange of oxygen, metabolic waste products, and carbon dioxide between blood and tissue cells.