proprietary (adj.)

mid-15c., "possessing worldly goods in excess of a cleric's needs," from Medieval Latin proprietarius "owner of property," noun use of Late Latin adjective proprietarius "of a property holder," from Latin proprietas "owner" (see property). Meaning "held in private ownership" is first attested 1580s. The word was used earlier in English as a noun meaning "proprietor," also "worldly person" (c. 1400), from a noun use in French and Medieval Latin.

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Definitions of proprietary from WordNet
proprietary (n.)
an unincorporated business owned by a single person who is responsible for its liabilities and entitled to its profits;
Synonyms: proprietorship
proprietary (adj.)
protected by trademark or patent or copyright; made or produced or distributed by one having exclusive rights;
`Tylenol' is a proprietary drug of which `acetaminophen' is the generic form