adjective

1. of or like a hair, esp. in being very slender
2. having a very small bore
3. in or of capillaries

Etymology: L capillaris < capillus, hair

noun pl. capillaries -·lar′·ies

1. a tube with a very small bore
   also capillary tube
2. any of the tiny blood vessels normally connecting the smallest arteries (arterioles) with the smallest veins (venules)