The Collaborative International Dictionary of English v.0.48:

Mezza majolica \Mez"za ma*jol"i*ca\ [It. See Mezzo;
   Majolica.] (Ceramics)
   Italian pottery of the epoch and general character of
   majolica, but less brilliantly decorated, esp. such pottery
   without tin enamel, but painted and glazed.
   [Webster 1913 Suppl.]