pigment - dry coloring matter (especially an insoluble powder to be mixed with a liquid to produce paint etc)

haemoglobin, Hb, hemoglobin - a hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues; "fish have simpler hemoglobin than mammals"

myoglobin - a hemoprotein that receives oxygen from hemoglobin and stores it in the tissues until needed

cytochrome - a class of hemoprotein whose principle biological function is as carriers of electrons