- Haemacyanin H[ae]m`a*cy"a*nin (-s[imac]"[.a]*n[i^]n), n.
[H[ae]ma- + Gr. ky`anos a dark blue substance.] (Physiol.
A substance found in the blood of the octopus, which gives to
it its blue color.
Note: When deprived of oxygen it is colorless, but becomes quickly blue in contact with oxygen, and is then generally called oxyh[ae]macyanin. A similar blue coloring matter has been detected in small quantity in the blood of other animals and in the bile. [1913 Webster]
The Collaborative International Dictionary of English. 2000.