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Webster 1913 Edition
Xanthin
Xan′thin
,Noun.
 [Gr. 
ξανθόσ 
yellow.] 1. 
same as 
xanthine
. 2. 
(Chem.) 
A yellow insoluble coloring matter extracted from yellow flowers; specifically, the coloring matter of madder. 
[Formerly written also 
xanthein
.] 3. 
(Chem.) 
One of the gaseous or volatile decomposition products of the xanthates, and probably identical with carbon disulphide. 
[Obs.]