pro·pri·e·tar·y / p(r)əˈprī-iˌterē/ • adj. of or relating to an owner or ownership: the company has a proprietary right to the property. ∎  (of a product) marketed under and protected by a registered trade name: proprietary brands of insecticide. ∎  behaving as if one were the owner of someone or something: he looked about him with a proprietary air.• n. an owner; proprietor. ∎ hist. esp. in North America, a grantee or owner of a colony who has been granted, as an individual or as part of a group, the full rights of self-government.

PROPRIETARY

As a noun, a proprietor or owner; one who has the exclusive title to a thing; one who possesses or holds the title to a thing in his or her own right; one who possesses the dominion or ownership of a thing in his or her own right.

As an adjective, belonging to ownership; owned by a particular person; belonging or pertaining to a proprietor; relating to a certain owner or proprietor.

Proprietary refers to ownership or characteristics relating to ownership. It describes all the rights that the owner of property can exercise. Proprietary articles are items that are manufactured and marketed under an exclusive right.

Municipal corporations have a proprietary function, a term describing the duty or capacity of a city to enter into business ventures or to perform discretionary acts in the best interests of the citizens. Proprietary functions differ from governmental functions, which are duties that a city performs as a political subdivision of a state.

proprietary grantee of one of certain Amer. colonies; proprietorship XVII; adj. XV. — Late L. proprietārius (in medL. as sb. holder of property), f. proprietās PROPERTY; see -ARY.
So proprietor XVII. alt. of prec. by irreg. substitution of suffix -TOR.