Fresco refers to a specific technique of mural painting where pigments are applied directly onto freshly laid wet lime plaster. In this process, water serves as the vehicle for dry-powder pigments, allowing them to merge with the plaster as it sets. This method ensures that the finished painting becomes an integral part of the wall structure.
The term is derived from the Italian adjective fresco, which means "fresh." It is distinguished from fresco-secco or secco mural painting techniques, which involve applying paint to dried plaster instead of wet. While the technique has been utilized since antiquity, it is most closely associated with the period of the Italian Renaissance.