by·word also by-word (bīwûrd′)
a. A proverbial expression; a proverb.
b. An often-used word or phrase.
2. One that represents a type, class, or quality: "Polyester got its déclassé reputation in the 1970s after cheap, poorly made double-knit leisure suits became a byword for bad taste" (Fortune).
3. An object of notoriety or interest: The eccentric poet was a byword in literary circles.
4. An epithet.
[Middle English byworde, from Old English bīword, translation of Latin prōverbium.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 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.