Iceland moss

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A brittle, grayish-brown lichen (Cetraria islandica) of Arctic and alpine regions, sometimes used as a food or in medicine.

from The Century Dictionary.

• noun etc. See the nouns.

from the GNU version of the Collaborative International Dictionary of English.

• (Bot.) A kind of lichen (Cetraria Icelandica) found from the Arctic regions to the North Temperate zone. It furnishes a nutritious jelly and other forms of food, and is used in pulmonary complaints as a demulcent.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A lichen, Cetraria islandica, that resembles a moss.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun 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