Watercolour pigment that has been mixed with a substance to give it body and make it opaque. It is also known as distemper, particularly when intended for wide application in e.g. stage painting; and it is often used interchangeably with gouache. And it may be two words body colour, and of course also bodycolor.
Traditionally, gouache is created by mixing the pigment with an opaque white filler (since 1834 usually zinc white), and bodycolour by mixing it with gelatin (isinglass from fish or size from animals), but the distinction is not always made. Like watercolour, it is made from pigment powder in a base of gum arabic.