n. pl. e·ter·ni·ties
1. Time without beginning or end; infinite time.
2. The state or quality of being eternal.
a. The timeless state following death.
b. The afterlife; immortality.
4. A very long or seemingly endless time: waited in the dentist's office for an eternity.
[Middle English eternite, from Old French, from Latin aeternitās, from aeternus, eternal; see ETERNAL.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.