An early Native American culture centered in the Ohio River valley from about the tenth century BC to about the second century AD, noted for its circular earthworks, elaborate burial mounds, and highly developed artistic style.
[After the Adena estate in south-central Ohio, the location of the type site of the culture.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.