cap·il·lar·y 
(kăpə-lĕr′ē)
(kăpə-lĕr′ē)adj.
1. Relating to or resembling a hair; fine and slender.
2. Having a very small internal diameter: a capillary tube.
3. Anatomy Of or relating to the capillaries.
4. Physics Of or relating to capillarity.
n. pl. cap·il·lar·ies
1. 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.
2. A tube with a very small internal diameter.
[From Latin capillāris, from capillus, hair.]