proprietary

1 of 2

adjective

pro·​pri·​e·​tary prə-ˈprī-ə-ˌter-ē 

1

: of, relating to, or characteristic of an owner or title holder

The investors have a proprietary interest in the land.

The publisher has proprietary rights to the manuscript.

2

: used, made, or marketed by one having the exclusive legal right

a proprietary process

The computer comes with the manufacturer's proprietary software.

They're custom-made with a proprietary blend of spices and fillings …

—Town & Country Magazine

3

: privately owned and managed and run as a profit-making organization

a proprietary clinic

proprietary

2 of 2

noun

pro·​pri·​e·​tary prə-ˈprī-ə-ˌter-ē 

plural proprietaries

1

: one that possesses, owns, or holds exclusive right to something

specifically : proprietor sense 1

2

: something that is used, produced, or marketed under exclusive legal right of the inventor or maker

specifically : a drug (such as a patent medicine) that is protected by secrecy, patent, or copyright against free competition as to name, product, composition, or process of manufacture

3

: a business secretly owned by and run as a cover for an intelligence organization

Did you know?

A proprietary process is a manufacturing process that others are forbidden to use, and a proprietary trademark is a name that only the owner can use. Legal rights of this kind are ensured by copyrights and patents. After a certain period of time, inventions and processes lose their legal protection, cease to be proprietary, and enter the "public domain", meaning that everyone can use them freely. Baseball fans often take a proprietary attitude toward their favorite team—that is, they behave more or less as if they own it, even though the only thing they may own is the right to yell from a bleacher seat till the end of a game.

Examples of proprietary in a Sentence

Adjective

By allowing less favorable results to remain buried, the agency puts proprietary interests ahead of the public interest, and doctors and the public come to believe prescription drugs are better than they are. That should stop. —Marcia Angell, New York Review of Books, 8 June 2006

It is a proprietary faith: no one better tell me what to do with my own land. —Lance Morrow, Time, 11 Sept. 2000

Many veterans have adopted a proprietary attitude toward the war, and they can get a bit belligerent about it. —Nicholas Proffitt, New York Times Book Review, 21 May 1989

The investors have a proprietary interest in the land.

The computer comes with the manufacturer's proprietary software.

“Merriam-Webster” is a proprietary name.

The journalist tried to get access to proprietary information.

Recent Examples on the Web

Adjective

The facility also works on integration for the Waymo Driver, which is what the company calls the proprietary hardware and software that enables self-driving. —Jackie Charniga, USA Today, 6 Nov. 2025

Those are all specific processes that are often proprietary and unique to individual companies, and actually require a degree of human decision-making that isn’t easily replicated from scrapable data. —Megan Poinski, Forbes.com, 4 Nov. 2025

Nammour’s team ended up building proprietary software that could find sensitive data, create privacy controls, and delete it, utilizing early versions of LLMs well before the November 2022 launch of ChatGPT created the global obsession around AI. —Leo Schwartz, Fortune, 3 Nov. 2025

Known for incorporating botanicals into nearly all their skin-care formulas, Chantecaille packs this brightening serum with white peony extract to help even tone and proprietary thiamidol to visibly fade dark spots over time. —Christa Joanna Lee, Allure, 3 Nov. 2025

Word History

Etymology

Adjective

Middle English proprietarye "possessing worldly goods beyond one's needs," borrowed from Medieval Latin propriētārius, going back to Late Latin, "of an owner or proprietor," adjective derivative of propriētārius "owner" — more at proprietary entry 2

Noun

Middle English proprietarie, borrowed from Anglo-French & Latin; Anglo-French, borrowed from Latin propriētārius, from propriētāt-, propriētās "ownership" + -ārius -ary entry 1 — more at property

First Known Use

Adjective

1589, in the meaning defined at sense 1

Noun

15th century, in the meaning defined at sense 1

Rhymes for proprietary

• accretionary
• apothecary
• bicentenary
• certiorari
• concessionary
• concretionary
• confectionary
• confectionery
• constabulary
• contemporary
• deflationary
• depositary

Kids Definition

proprietary

1 of 2 noun

pro·​pri·​etary

p(r)ə-ˈprī-ə-ˌter-ē

plural proprietaries

: proprietor sense 1

proprietary

2 of 2 adjective

1

a

: of or relating to a proprietor

proprietary rights

b

: resembling that of a proprietor

a proprietary pride in their hometown

2

: made and sold by one having the exclusive right to manufacture and sell

a proprietary drug

3

: privately owned and managed

a proprietary nursing home

Medical Definition

proprietary

1 of 2 noun

pro·​pri·​e·​tary p(r)ə-ˈprī-ə-ˌter-ē 

plural proprietaries

: something that is used, produced, or marketed under exclusive legal right of the inventor or maker

specifically : a drug (as a patent medicine) that is protected by secrecy, patent, or copyright against free competition as to name, product, composition, or process of manufacture

proprietary

2 of 2 adjective

1

: used, made, or marketed by one having the exclusive legal right

a proprietary drug

2

: privately owned and managed and run as a profit-making organization

a proprietary clinic

Legal Definition

proprietary

1 of 2 noun

pro·​pri·​e·​tary prə-ˈprī-ə-ˌter-ē 

plural proprietaries

1

: something that is used, produced, or marketed under exclusive legal right of the inventor or maker

specifically : a drug (as a patent medicine) that is protected by secrecy, patent, or copyright against free competition as to name, product, composition, or process of manufacture

2

: a business secretly owned by and run as a cover for an intelligence operation

proprietary

2 of 2 adjective

1

a

: held as property of a private owner

b

: of, relating to, or characteristic of a proprietor

proprietary rights

2

: used, made, or marketed by one having the exclusive legal right

a proprietary process

3

: privately owned and managed and run as a profit-making organization

a proprietary insurer

a proprietary clinic

4

: of or relating to the acts of a municipality which profit or benefit the municipality and for which it is answerable in negligence