what is in gesso
Definition of GESSO. 1. : plaster of paris or gypsum prepared with glue for use in painting or making bas-reliefs. 2. : a paste prepared by mixing whiting with size or glue and spread upon a surface to fit it for painting or gilding. â gesÂ·soed \-(Ë)sÅd\ adjective.See gesso defined for kids.efinition of GESSO. 1. : plaster of paris or gypsum prepared with glue for use in painting or making bas-reliefs. 2. : a paste prepared by mixing whiting with size or glue and spread upon a surface to fit it for painting or gilding. â gesÂ·soed \-(Ë)sÅd\ adjective. See gesso defined for kids.