The term Mural Undercoat is a combination of two words, Gesso (5 letters) and Mural. Gesso is a white paint mixture made of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used as an undercoat for murals, providing a smooth surface for the paint to adhere to. Mural is a painting or other work of art executed directly on a wall, ceiling, or other large permanent surface. Together, Mural Undercoat refers to the use of Gesso as an undercoat for a mural.