1. Of or relating to a proprietor or to ownership: had proprietary rights.
2. Privately owned, as a business: a proprietary hospital.
3. Owned by a private individual or corporation under a trademark or patent: a proprietary drug.
n. pl. pro·pri·e·tar·ies
1. A proprietor or group of proprietors.
2. Ownership; proprietorship.
3. A proprietary medicine.
4. One granted ownership of a proprietary colony.
[From Middle English proprietarie, owner of property, from Old French proprietaire and from Medieval Latin proprietārius, both from Late Latin, of a property owner, from Latin proprietās, ownership; see PROPERTY.]
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.