n 1  :  the dried and bleached plants of a red alga of the genus Chondrus(C. crispus) and one of a related genus (Gigartina mamillosa) that are used as an agent for thickening or emulsifying or as a demulcent (as in cookery or pharmacy) - called also chondrus   2  :  either of the two red algae that are the source of Irish moss - called also carrageen  .
 
 
 
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