co·ad·u·nate (kō-ăjə-nĭt, -nāt′)
Closely joined; grown together; united.
[Late Latin coadūnātus, past participle of coadūnāre, to combine : Latin co-, co- + Latin adūnāre, to unite (ad-, ad- + ūnus, one; see oi-no- in the Appendix of Indo-European roots).]
co·ad′u·nation (-nāshən) n.
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.