n. pl. cer·tain·ties
1. The fact, quality, or state of being certain, especially:
a. Inevitability: the certainty of death.
b. The quality of being established as true: the certainty that the earth orbits the sun.
c. Confidence; assurance: his certainty that things would get better.
2. Something that is clearly established or assured: "On the field of battle there are no certainties" (Tom Clancy).
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.