pref·er·en·tial 
(prĕf′ə-rĕnshəl)
(prĕf′ə-rĕnshəl)adj.
1. Of, relating to, or giving advantage or preference: preferential treatment.
2. Manifesting or originating from partiality or preference: preferential tariff rates.
pref′er·ential·ism n.
pref′er·ential·ist n.
pref′er·ential·ly adv.