n. pl. psy·chol·o·gies
1. The science that deals with mental processes and behavior.
2. The emotional and behavioral characteristics of an individual, a group, or those engaged in a given activity: the psychology of war.
3. Subtle tactical action or argument used to manipulate or influence another: He used poor psychology on his employer when trying to make the point.
4. Philosophy The branch of metaphysics that studies the soul, the mind, and the relationship of life and mind to the functions of the body.
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.