trifoliate Syllabification: (tri·fo·li·ate)Pronunciation: /trīˈfōlē-it, -ˌāt/Definition of trifoliate adjective (of a compound leaf) having three leaflets:dark green trifoliate leaves (of a plant) having trifoliate leaves. (of an object or design) having the form of a trifoliate leaf:a bronze trifoliate key handle noun a plant with trifoliate leaves:poison ivy is a thornless trifoliatetrifoliate in other Oxford dictionaries Definition of trifoliate in the British & World English dictionary