noun one of the similar branches of the framework of a leaf.
2. vein ·vt to form or mark with veins; to fill or cover with veins.
3. vein ·noun a fissure, cleft, or cavity, as in the earth or other substance.
4. vein ·noun a train of association, thoughts, emotions, or the like; a current; a course.
5. vein ·noun one of the ribs or nervures of the wings of insects. ·see venation.
6. vein ·noun one of the vessels which carry blood, either venous or arterial, to the heart. ·see artery, 2.
7. vein ·noun a streak or wave of different color, appearing in wood, and in marble and other stones; variegation.
8. vein ·noun peculiar temper or temperament; tendency or turn of mind; a particular disposition or cast of genius; humor; strain; quality; also, manner of speech or action; as, a rich vein of humor; a satirical vein.
9. vein ·noun a narrow mass of rock intersecting other rocks, and filling inclined or vertical fissures not corresponding with the stratification; a lode; a dike;
often limited, in the language of miners, to a mineral vein or lode, that is, to a vein which contains useful minerals or ores.