[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] : WordNet (r) 2.0

mule deer
     n : long-eared deer of western north america with two-pronged
         antlers syn: burro deer, odocoileus hemionus
see also:
burro deer odocoileus hemionus 

Deer >> D Words
Deer, definition of term: Deer
deer_pag1.html

Mule >> M Words
Mule, definition of term: Mule
mule_pag1.html

Mule Skinner >> M Words
Mule Skinner, definition of term: Mule Skinner
mule+skinner_pag1.html

Musk Deer >> M Words
Musk Deer, definition of term: Musk Deer
musk+deer_pag1.html