artists' paint made with a water-soluble binder such as gum arabic, and thinned with water rather than oil, giving a transparent colour:a self-portrait in watercolour [count noun]:the technique involved the use of watercolours
[count noun] a picture painted with watercolours.
the art of painting with watercolours, especially using a technique of producing paler colours by diluting rather than by adding white.
watercolour in other Oxford dictionaries
Definition of watercolour in the US English dictionary