/ (ˌhiːməʊˈsaɪənɪn) /
a blue copper-containing respiratory pigment in crustaceans and molluscs that functions as haemoglobin
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Examples from the Web for haemocyanin
The blood-corpuscles are large amoebiform cells, and the blood-plasma is coloured blue by haemocyanin.