1. A peculiarity of behavior; an idiosyncrasy: "Every man had his own quirks and twists" (Harriet Beecher Stowe).
2. An unpredictable or unaccountable act or event; a vagary: a quirk of fate.
3. A sudden sharp turn or twist: a quirk of the head.
4. Architecture A lengthwise groove on a molding between the convex upper part and the soffit.
5. Archaic An equivocation; a quibble.
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.