Cetraria islandica n 1: lichen with branched flattened partly erect thallus that grows in mountainous and Arctic regions; used as a medicine or food for humans and livestock; a source of glycerol [syn: {Iceland moss}, {Iceland lichen}, {Cetraria islandica}]
Cetrarin \Cet"ra*rin\, n. [From Cetraria Islandica, the scientific name of Iceland moss.] (Chem.) A white substance extracted from the lichen, Iceland moss ({Cetraria Islandica}). It consists of several ingredients, among which is cetraric acid, a white, crystalline, bitter substance. [1913 Webster]