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