[1] : The Collaborative International Dictionary of English v.0.48

mule \mule\ m=ul, n. f., a she-mule, l. mula, fem. of
   mulus; cf. gr. my`klos, mychlo`s. cf. as. m=ul, fr. l.
   mulus. cf. mulatto.
   1. zool. a hybrid animal; specifically, one generated
      between an ass and a mare. sometimes the term is applied
      to the offspring of a horse and a she-ass, but that hybrid
      is more properly termed a hinny. see hinny.
      1913 webster

   note: mules are much used as draught animals. they are hardy,
         and proverbial for stubbornness.
         1913 webster

   2. bot. a plant or vegetable produced by impregnating the
      pistil of one species with the pollen or fecundating dust
      of another; -- called also hybrid.
      1913 webster

   3. a very stubborn person.
      1913 webster

   4. a machine, used in factories, for spinning cotton, wool,
      etc., into yarn or thread and winding it into cops; --
      called also jenny and mule-jenny.
      1913 webster

   5. a slipper that has no fitting around the heel.

   syn: mules, scuff, scuffs.
        wordnet 1.5

   mule armadillo zool., a long-eared armadillo tatusia
      hybrida, native of buenos ayres; -- called also mulita.
      see illust. under armadillo.

   mule deer zool., a large deer cervus macrotis syn.
      cariacus macrotis of the western united states. the
      name refers to its long ears.

   mule pulley mach., an idle pulley for guiding a belt
      which transmits motion between shafts that are not
      parallel.

   mule twist, cotton yarn in cops, as spun on a mule; -- in
      distinction from yarn spun on a throstle frame.
      1913 webster
see also:
mulatto hinny hinny hybrid jenny mule-jenny 
mule armadillo mulita armadillo mule deer cervus macrotis 
cariacus macrotis mule pulley mule twist 

[2] : The Collaborative International Dictionary of English v.0.48

deer \deer\ d=er, n. sing.  pl. oe. der, deor, animal,
   wild animal, as. de'or; akin to d. dier, ofries. diar, g.
   thier, tier, icel. d=yr, dan. dyr, sw. djur, goth. dius; of
   unknown origin. root71.
   1. any animal; especially, a wild animal. obs. --chaucer.
      1913 webster

            mice and rats, and such small deer.   --shak.
      1913 webster

            the camel, that great deer.           --lindisfarne
                                                  ms.
      1913 webster

   2. zool. a ruminant of the genus cervus, of many species,
      and of related genera of the family cervidae. the
      males, and in some species the females, have solid
      antlers, often much branched, which are shed annually.
      their flesh, for which they are hunted, is called
      venison.
      1913 webster

   note: the deer hunted in england is cervus elaphus, called
         also stag or red deer; the fallow deer is cervus
         dama; the common american deer is cervus
         virginianus; the blacktailed deer of western north
         america is cervus columbianus; and the mule deer of
         the same region is cervus macrotis. see axis,
         fallow deer, mule deer, reindeer.
         1913 webster

   note: deer is much used adjectively, or as the first part of
         a compound; as, deerkiller, deerslayer, deerslaying,
         deer hunting, deer stealing, deerlike, etc.
         1913 webster

   deer mouse zool., the white-footed mouse peromyscus
      leucopus, formerly hesperomys leucopus of america.

   small deer, petty game, not worth pursuing; -- used
      metaphorically. see citation from shakespeare under the
      first definition, above. "minor critics . . . can find
      leisure for the chase of such small deer." --g. p. marsh.
      1913 webster
see also:
cervus cervidae venison cervus elaphus red deer cervus dama 
cervus virginianus cervus columbianus cervus macrotis axis fallow deer 
mule deer reindeer deer mouse peromyscus leucopus hesperomys leucopus 
small deer 

Macrotis >> M Words
Macrotis, definition of term: Macrotis
macrotis_pag1.html

Cervus >> C Words
Cervus, definition of term: Cervus
cervus_pag1.html