n. Abbr. e
A stable elementary particle in the lepton class having a negative electric charge of 1 elementary unit (about 1.602 × 10-19 coulombs) and a mass of about 9.11 × 10-28 grams. Electrons are found in shells orbiting the nuclei of atoms and can also move freely through space as cathode rays in a cathode-ray tube or as beta particles emitted by radioactive nuclei, or flow in a current through a conducting material impelled by an electric potential difference.
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.