a. Conforming to dietary laws; ritually pure: kosher meat.
b. Observing dietary laws: a kosher household.
c. Selling or serving food prepared in accordance with dietary laws: a kosher restaurant.
2. Informal Legitimate; permissible: Is it kosher to wear jeans in the office?
tr.v. ko·shered, ko·sher·ing, ko·shersIdiom:
To make proper or ritually pure.
To observe Jewish dietary laws.
[Yiddish kosher, from Ashkenazi Hebrew kóšer, from Hebrew kāšēr, fitting, proper, from kāšēr, to be fitting, to succeed; see kṯr in the Appendix of Semitic roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.