co·her·ent (kō-hîrənt, -hĕr-)
1. Sticking together; cohering.
a. Marked by an orderly, logical, and aesthetically consistent relation of parts: a coherent essay.
b. Able to express one's thoughts in a clear and orderly manner: a first responder who remained coherent during the crisis.
3. Physics Of, relating to, or having waves with similar direction, amplitude, and phase that are capable of exhibiting interference.
4. Of or relating to a system of units of measurement in which a small number of basic units are defined from which all others in the system are derived by multiplication or division only.
5. Botany Sticking to but not fused with a part or an organ of the same kind.
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.