Gouache is one type of watermedia, designed to be used with opaque methods of painting. The term, derived from the Italian guazzo, also refers to paintings using this opaque method.
Gouache has a considerable history going back over 600 years. It is similar to watercolor because it can be re-wet and the paint can become infused with its paper support. It can also form a superficial layer like acrylic or oil paint. Also like watercolor, gouache dries to a matte finish.