cer·ti·tude (sûrtĭ-td′, -tyd′)
1. The state of being certain or convinced of something; complete assurance; confidence: Who can say with certitude how strong the economy will be next year?
2. Something that is assured or believed to be true: "serene certitudes instilled in me by my family and teachers" (Garry Wills).
[Middle English, from Late Latin certitūdō, from Latin certus, certain; see CERTAIN.]
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.