a. Anatomy Any of the membranous tubes that form a branching system and carry blood to the heart from the cells, tissues, and organs of the body.
b. A blood vessel of any kind; a vein or artery: felt the blood pounding in her veins.
c. Something that looks like a blood vessel, such as the hindgut of a shrimp.
2. Botany One of the strands of vascular tissue that form the conducting and supporting framework in a leaf or other expanded plant organ. Also called nervure.
3. Zoology One of the thickened cuticular ribs that form the supporting network of the wing of an insect and that often carry hemolymph. Also called nervure.
4. Geology A regularly shaped and lengthy occurrence of an ore; a lode.
5. A long wavy strip of a different shade or color, as in wood or marble, or as mold in cheese.
6. A fissure, crack, or cleft.
7. A pervading character or quality; a streak: "All through the interminable narrative there ran a vein of impressive earnestness" (Mark Twain).
a. A transient attitude or mood.
b. A particular turn of mind: spoke later in a more serious vein.
tr.v. veined, vein·ing, veins
1. To supply or fill with veins.
2. To mark or decorate with veins.
[Middle English veine, from Old French, from Latin vēna.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.