n. pl. en·tro·pies
1. Symbol S For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work.
2. A measure of the disorder or randomness in a closed system.
3. A measure of the loss of information in a transmitted message.
4. The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity.
5. The deterioration of a system or society, especially when it seems inevitable: city activists who fought entropy by organizing neighborhood groups.
[German Entropie : Greek en-, in; see EN-2 + Greek tropē, transformation; see trep- in the Appendix of Indo-European roots.]
en·tropic (ĕn-trōpĭk, -trŏpĭk) adj.
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.