a. Of or relating to the foundation or base; elementary: the fundamental laws of the universe.
b. Forming or serving as an essential component of a system or structure; central: an example that was fundamental to the argument.
c. Of great significance or entailing major change: a book that underwent fundamental revision.
2. Of or relating to the lowest possible frequency or the lowest frequency component of a vibrating element, system, periodic wave, or quantity: a fundamental chord.
3. Music Having the root in the bass: a fundamental chord.
1. Something that is an essential or necessary part of a system or object.
2. The lowest frequency of a periodically varying quantity or of a vibrating system.
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.