proprietarial UK /pɹəˌpɹaɪ.əˈtɛəɹi.əl/US /pɹəˌpɹaɪ.əˈtɛɹi.əl/ adjective2 •Pertaining to proprietarians or proprietarianism (in colonial North America).In Charleston, the aftermath of the Yamassee War was one of reorganization, regulation and a massive political shift as the colony moved from proprietarial control to become a royal colony. — 2015 •Proprietary or proprietorial; pertaining to property or ownership (of property).