vein

American  

[veyn] / veɪn /

noun

1. one of the system of branching vessels or tubes conveying blood from various parts of the body to the heart.

2. (loosely) any blood vessel.

3. one of the riblike thickenings that form the framework of the wing of an insect.

4. one of the strands or bundles of vascular tissue forming the principal framework of a leaf.

5. any body or stratum of ore, coal, etc., clearly separated or defined.

   a rich vein of coal.

6. a body or mass of igneous rock, deposited mineral, or the like occupying a crevice or fissure in rock; lode.

7. a natural channel or watercourse beneath the surface of the earth.

8. the water running through such a channel.

9. a streak or marking, as of a different shade or color, running through marble, wood, etc.

10. a condition, mood, or temper.

    a vein of pessimism.

11. a tendency, quality, or strain traceable in character, conduct, writing, etc.; manner or style.

    to write in a poetic vein.

    Synonyms:

    thread, hint, touch, streak, tone

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verb (used with object)

1. to furnish with veins.

2. to mark with lines or streaks suggesting veins.

3. to extend over or through in the manner of veins.

   Broad new highways vein the countryside.

vein British  

/ veɪn /

noun

1. any of the tubular vessels that convey oxygen-depleted blood to the heart Compare pulmonary vein artery

2. any of the hollow branching tubes that form the supporting framework of an insect's wing

3. any of the vascular strands of a leaf

4. a clearly defined mass of ore, mineral, etc, filling a fault or fracture, often with a tabular or sheetlike shape

5. an irregular streak of colour or alien substance in marble, wood, or other material

6. a natural underground watercourse

7. a crack or fissure

8. a distinctive trait or quality in speech, writing, character, etc; strain

   a vein of humour

9. a temporary disposition, attitude, or temper; mood

   the debate entered a frivolous vein

10. a parting in hair

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verb

1. to diffuse over or cause to diffuse over in streaked patterns

2. to fill, furnish, or mark with or as if with veins

vein Scientific  

/ vān /

1. Any of the blood vessels that carry blood toward the heart from the body's cells, tissues, and organs. Veins are thin-walled and contain valves that prevent the backflow of blood. All veins except the pulmonary vein carry blood with low levels of oxygen.

2. One of the narrow, usually branching tubes or supporting parts forming the framework of an insect's wing or a leaf. Veins in insect wings carry hemolymph and contain a nerve. Veins in leaves contain vascular tissue, with the xylem usually occurring on the upper side of the vein (bringing in water and nutrients) and the phloem on the lower side (carrying away food).

3. See more at leaf venation

4. A long, narrow deposit of mineral or rock that fills the void formed by a fracture or fault in another rock. The mineralogy of the host rock surrounding the vein is often altered where it is in contact with the vein because of chemical reactions between the two rock types.

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Other Word Forms

• intervein
  verb (used with object)
• interveinal
  adjective
• subvein
  noun
• unveined
  adjective
• veinal
  adjective
• veinless
  adjective
• veinlike
  adjective
• veiny
  adjective

Etymology

Origin of vein

1250–1300; Middle English veine < Old French < Latin vēna vein of the body, channel, ore deposit

Explanation

A vein is a blood vessel. If you've ever donated blood, you know that having a needle put in your vein by a health care worker is not nearly as scary as it sounds. Although it mainly describes part of the body's circulatory system, vein can also refer to a pattern that looks like a vein in your body. For example, you can describe the streaks of color that run through blue cheese as veins of greenish-blue. Similarly, a theme or idea that continues appearing throughout a book could be called a vein. The trickiest thing about the word vein is trying not to confuse it with its homophones — vane (as in weather vane) and vain (as in conceited).

Example Sentences

Swenson plans to fly out for Vein’s service, Jon Vein said.

From Los Angeles Times • May 5, 2026

When the Palisades fire erupted, Vein sprang into action.

From Los Angeles Times • May 5, 2026

At Vein, a nightclub not far off, Tiwa Savage, one of Nigeria's biggest Afrobeats stars, took to the mic.

From Barron's • Dec. 22, 2025

“The community does not want higher density,” Vein said.

From Los Angeles Times • Jul. 30, 2025

For in like Manner those inflamed Tracts which are suspended in the Air, flash from a Flame that runs from one Extreme to the other, wherever the Vein of Nourishment leads it.

From The Shepherd of Banbury's Rules to Judge of the Changes of the Weather, Grounded on Forty Years' Experience by Claridge, John

Related Words

• hair
• lode
• nerve
• seam
• stripe