reindeer moss(n = noun.plant) arctic moss, cladonia rangiferina, reindeer lichen - an erect greyish branching lichen of Arctic and even some north temperate regions constituting the chief food for reindeer and caribou and sometimes being eaten by humans;
is a kind of lichen
is a member of cladonia, genus cladonia

acrocarpous moss, arctic moss, beard moss, black moss, bog moss, club moss, iceland moss, irish moss, little club moss, long moss, moss, moss agate, moss animal, moss campion, moss family, moss genus, moss green, moss hart, moss locust, moss phlox, moss pink, peat moss, pleurocarpous moss, reindeer, reindeer lichen, rose moss, scale moss, sea moss, spanish moss, sphagnum moss, spike moss, staghorn moss