adj. & n.
adj. 1 of or like a hair. 2 (of a tube) of hairlike internal diameter. 3 of one of the delicate ramified blood vessels intervening between arteries and veins.
n. (pl. -ies) 1 a capillary tube. 2 a capillary blood vessel. capillary action = CAPILLARITY.
[ L capillaris f. capillus hair ]