1. A series of events in which each induces or influences the next.
2. Physics A multistage nuclear reaction, especially a self-sustaining series of fissions in which the release of neutrons from the splitting of one atom leads to the splitting of others.
3. Chemistry A series of reactions in which one product of a reacting set is a reactant in the following set.
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.