fresco

Concise Oxford English Dictionary © 2008 Oxford University Press:
fresco /ˈfrɛskəʊ/

▶noun (pl. frescoes or frescos) a type of painting done in watercolour on wet plaster on a wall or ceiling, in which the colours penetrate the plaster and become fixed as it dries.

– derivatives
frescoed adjective.

– origin C16: Ital., lit. ‘cool, fresh’; first recorded in the phr. in fresco, representing Ital. affresco, al fresco ‘on the fresh (plaster)’.