Transparent aqueous based paint produced by mixing ground pigments with water and, generally, gum arabic; paints made with vegetable gum binders were used by Egyptian, Greek, and Roman artists for wall paintings. Japanese and Chinese painters extensively used watercolor paints on silk panels and delicate paper scrolls. In the 16th through18th century, watercolor paints were used for miniature illustrations on porcelain, ivory, cards, books and manuscripts. By the 18th and early 19th centuries, watercolors rapidly increased in popularity due to the availability of small cakes of watercolor paints in metal pans, usually applied to a paper support by using a brush.

Source: Art and Architecture Thesaurus

http://vocab.getty.edu/page/aat/300015045