a. The superciliary ridge over the eyes.
b. The eyebrow.
c. The forehead.
2. A facial expression; countenance: "Speak you this with a sad brow?" (Shakespeare).
3. The projecting upper edge of a steep place: the brow of a hill.
[Middle English, from Old English brū; see bhrū- in the Appendix of Indo-European roots.]
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.