1. An act, assertion, or belief that unintentionally deviates from what is correct, right, or true.
2. The condition of having incorrect or false knowledge.
3. The act or an instance of deviating from an accepted code of behavior.
4. A mistake.
5. Mathematics The difference between a computed or measured value and a true or theoretically correct value.
6. Abbr. E Baseball A defensive fielding or throwing misplay by a player when a play normally should have resulted in an out or prevented an advance by a base runner.
[Middle English errour, from Old French, from Latin error, from errāre, to err; see ers- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.