gesso

/ˈdʒɛsoʊ/

Gesso is a substance similar to white paint that artists use to prepare a surface for painting. Gesso is typically made of glue, chalk, and white pigment.

Before you paint a portrait on a square of canvas or a piece of wood, you may want to coat your painting surface with gesso. After it dries, gesso creates an even base that holds paint well — similar to the primer house painters use before applying paint. Gesso means "chalk" or "plaster" in Italian, from the Latin gypsum, also "plaster," and the Greek root gypsos, "chalk."

Definitions of gesso

1. noun

   gypsum or plaster of Paris spread on a surface to make it suitable for painting or gilding (or a surface so prepared)
   type of:

   gypsum

   a common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)

   plaster, plaster of Paris

   any of several gypsum cements; a white powder (a form of calcium sulphate) that forms a paste when mixed with water and hardens into a solid; used in making molds and sculptures and casts for broken limbs