1. A large building for sheltering livestock, storing hay or other agricultural products, or housing equipment used for operating a farm.
2. A large shed for the housing of vehicles, such as railroad cars.
3. A particularly large, typically bare building: lived in a barn of a country house.
4. Abbr. b Physics A unit of area equal to 10-24 square centimeters, used to measure cross sections in nuclear physics.
[Middle English bern, from Old English berærn : bere, barley; see bhares- in the Appendix of Indo-European roots + ærn, house.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.