mo·res (môrāz′, -ēz)
1. The accepted traditional customs and usages of a particular social group.
2. Moral attitudes.
3. Manners; ways.
[Latin mōrēs, pl. of mōs, custom; see mē-1 in the Appendix of Indo-European roots.]
Usage Note: Although educated 19th-century speakers of English would pronounce mores as (môrēz) according to the customary pronunciation of Latin in English-speaking countries at that time, 75 percent of the Usage Panel in 2005 found this same pronunciation unacceptable (although 5 percent actually preferred it). Nowadays, the accepted pronunciation is (môrāz), with a long a as in days and a (z) sound at the end. It is incorrect to pronounce it as a single syllable (môrz), and the pronunciation ending with an (s) sound, which more closely resembles the way the Latin word was actually pronounced by the Romans, may sound pretentious.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.