- gypsum or plaster of Paris prepared with glue for use as a surface for painting.
- any plasterlike preparation to prepare a surface for painting, gilding, etc.
- a prepared surface of plaster or plasterlike material for painting, gilding, etc.
- a white ground of plaster and size, used esp in the Middle Ages and Renaissance to prepare panels or canvas for painting or gilding
- any white substance, esp plaster of Paris, that forms a ground when mixed with water
