Source : Webster's Revised Unabridged Dictionary (1913)

Reindeer \Rein"deer`\ (r?n"d?r), n. [Icel. hreinn reindeer + E.
   deer. Icel. hreinn is of Lapp or Finnish origin; cf. Lappish
   reino pasturage.] [Formerly written also {raindeer}, and
   {ranedeer}.] (Zool.)
   Any ruminant of the genus {Rangifer}, of the Deer family,
   found in the colder parts of both the Eastern and Western
   hemispheres, and having long irregularly branched antlers,
   with the brow tines palmate.

   Note: The common European species ({R. tarandus}) is
         domesticated in Lapland. The woodland reindeer or
         caribou ({R. caribou}) is found in Canada and Maine
         (see {Caribou}.) The Barren Ground reindeer or caribou
         ({R. Gr[oe]nlandicus}), of smaller size, is found on
         the shores of the Arctic Ocean, in both hemispheries.

   {Reindeer moss} (Bot.), a gray branching lichen ({Cladonia
      rangiferina}) which forms extensive patches on the ground
      in arctic and even in north temperature regions. It is the
      principal food of the Lapland reindeer in winter.

   {Reindeer period} (Geol.), a name sometimes given to a part
      of the Paleolithic era when the reindeer was common over
      Central Europe.

Source : WordNet®

reindeer moss
     n : an erect grayish branching lichen of Arctic and even some
         north temperate regions constituting the chief food for
         reindeer and caribou and sometimes being eaten by humans
         [syn: {reindeer lichen}, {arctic moss}, {Cladonia
         rangiferina}]