noun, plural -coes, -cos, verb, -coed, -co⋅ing.| 1. | Also called buon fresco, true fresco. the art or technique of painting on a moist, plaster surface with colors ground up in water or a limewater mixture. Compare fresco secco. |
| 2. | a picture or design so painted. |
| 3. | to paint in fresco. |
A painting on wet plaster. When the plaster dries, the painting is bonded to the wall. Fresco was a popular method for painting large murals during the Renaissance. The Last Supper, by Leonardo da Vinci, is a fresco, as are the paintings by Michelangelo in the Sistine Chapel.