phycoxanthin (?fa?k??zæn??n) n (Biochemistry) biochem a yellow pigment found in brown seaweeds and types of algaeCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014