Lewis Short
(adjective) : proprĭĕtārĭus, ii, m.proprietas
* An owner, proprietor (post-class.), Dig. 7, 1, 15 et saep.—As : proprietaria res,belonging to one as his property, proprietary,Paul. Sent. 5, 7, 3.
Charlton T. Lewis, Charles Short, A Latin Dictionary