Mid 18th century. From the title of Louis Jules Mancini Mazarini, Duc de Nivernois, and French ambassador to London 1762–3. Nivernois (now Nivernais) was the name of a former province of central France with Nevers as its capital; compare French Nivernois inhabitant of Nevers, inhabitant of Nivernais, characterestic of Nivernais or Nevers.