1. Behavior or attitude that is boldly arrogant or offensive; effrontery: She was offended at the stranger's presumption in speaking in such an casual manner.
2. The act of presuming or accepting something as true: the presumption of innocence of the accused.
3. A condition or basis for accepting or presuming something.
4. Law A conclusion applied by law as to the correctness of some fact, ordinarily subject to rebuttal by contrary evidence.
[Middle English presumpcion, from Old French, from Late Latin praesūmptiō, praesūmptiōn-, from Latin, anticipation, from praesūmptus, past participle of praesūmere, to anticipate; see PRESUME.]
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.