Quiz: Remember the definition of mal de mer?
c.1300, properte, "nature, quality," later "possession, thing owned" (early 14c., a sense rare before 17c.), from an Anglo-French modification of Old French propriete "individuality, peculiarity; property" (12c., Modern French propreté; cf. propriety), from Latin proprietatem (nominative proprietas) "ownership, a property, propriety, quality," literally "special character" (a loan-translation of Greek idioma), noun of quality from proprius "one's own, special" (see proper). For "possessions, private property" Middle English sometimes used proper goods. Hot property "sensation, a success" is from 1947 in "Billboard" stories.