Hæm′a‐cy″a‐nin (–sī″ȧ‐nĭn), n. [Hæma- + Gr. κύανοσ a dark blue substance.] (Physiol. Chem.) A substance found in the blood of the octopus, which gives to it its blue color.
☞ When deprived of oxygen it is colorless, but becomes quickly blue in contact with oxygen, and is then generally called oxyhæmacyanin. A similar blue coloring matter has been detected in small quantity in the blood of other animals and in the bile.