Chromatophore

Webster's Dictionary of the English Language

·noun One of the granules of protoplasm, which in mass give color to the part of the plant containing them.

II. Chromatophore ·noun A contractile cell or vesicle containing liquid pigment and capable of changing its form or size, thus causing changes of color in the translucent skin of such animals as possess them. They are highly developed and numerous in the cephalopods.