capillary

UK: /kəˈpɪləri/ US: /ˈkæpəˌlɛri/ ,(kap′ə ler′ē)

Inflections of 'capillary' (n): npl: capillaries

WordReference Random House Learner's Dictionary of American English © 2026

cap•il•lar•y /ˈkæpəˌlɛri/   n., pl. -ies, adj. 
n. [countable]

1. Anatomy one of the tiny, hairlike blood vessels between the arteries and the veins.

adj. [before a noun]

2. Physics of or relating to the attraction or the pushing away between a liquid and a solid:
   Capillary action causes oil to rise in the wick of a lantern.

WordReference Random House Unabridged Dictionary of American English © 2026

cap•il•lar•y  (kap′ə ler′ē), adj., n., pl. -lar•ies. 
adj. 

1. pertaining to or occurring in or as if in a tube of fine bore.
2. resembling a strand of hair;
   hairlike.
3. Physics
   • pertaining to capillarity.
   • of or pertaining to the apparent attraction or repulsion between a liquid and a solid, observed in capillarity.
4. Anatomy pertaining to a capillary or capillaries.

n. 

5. Anatomy one of the minute blood vessels between the terminations of the arteries and the beginnings of the veins.
6. Physics Also called cap′illary tube′. a tube with a small bore.

• Latin capillāris pertaining to hair, equivalent. to capill(us) hair + -āris -ar¹) + -ary
• capill(ar) (obsolete, 1570–80

Collins Concise English Dictionary © HarperCollins Publishers::

capillary / kəˈpɪlərɪ/ adjective

1. resembling a hair; slender
2. (of tubes) having a fine bore
3. of or relating to any of the delicate thin-walled blood vessels that form an interconnecting network between the arterioles and the venules
4. of or relating to capillarity

noun ( -laries)

1. any of the capillary blood vessels
2. a fine hole or narrow passage in any substance

Etymology: 17th Century: from Latin capillāris, from capillus hair