ni·cae·an I. \(ˈ)nī|sēən\adjective Usage: usually capitalized Etymology:Nicaea, ancient city, Asia Minor (from Latin) + English -an — more at nicene : nicene II. noun (-s) 1.capitalized: a native or inhabitant of Nicaea 2.usually capitalized: a 4th or 5th century adherent of the Nicene Creed