v. flared, flar·ing, flares
1. To flame up with a bright, wavering light.
2. To burst into intense, sudden flame.
a. To erupt or intensify suddenly: Tempers flared at the meeting. His allergies flared up.
b. To become suddenly angry. Used with up: He flared up when she alluded to his financial difficulties.
c. To make a sudden angry verbal attack. Used with out: flared out at his accusers.
4. To expand or open outward in shape: a skirt that flares from the waist; nostrils that flared with anger.
1. To cause to flame up.
2. To signal with a blaze of light.
1. A brief wavering blaze of light.
2. A device that produces a bright light for signaling, illumination, or identification.
3. An outbreak, as of emotion or activity.
4. An expanding or opening outward.
5. An unwanted reflection within an optical system or the resultant fogging of the image.
6. A solar flare.
a. Football A short pass to a back running toward the sideline.
b. Baseball A fly ball hit a short distance into the outfield.
a. An area of redness on the skin surrounding the primary site of infection or irritation.
b. A sudden worsening of the symptoms of a disease or condition: treating an arthritis flare.
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.