aux.v. Past tense of can1.
1. Used to indicate ability or permission in the past: I could run faster then. Only men could go to the club in those days.
2. Used with hypothetical or conditional force: If we could help, we would.
3. Used to indicate tentativeness or politeness: I could be wrong. Could you come over here?
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.