pref·er·en·tial \|prefə|renchəl\adjective Etymology: Medieval Latin praeferentia preference + English -al 1.: of, relating to, or showing preference : offering or constituting an advantage < preferential treatment > 2.: of, relating to, employing, or creating a preference in trade relations < a preferential rate > • pref·er·en·tial·ly\-chəlē, -li\adverb