adj.1 a of, holding, or concerning property (the proprietary classes). b of or relating to a proprietor (proprietary rights).
2 held in private ownership.
Phrases and idioms:
proprietary medicine any of several drugs, medicines, etc. produced by private companies under brand names. proprietary name (or term) a name of a product etc. registered by its owner as a trade mark and not usable by another without permission.
Etymology: LL proprietarius (as PROPERTY)