The Collaborative International Dictionary of English v.0.48:

Myrrh \Myrrh\, n. [OE. mirre, OF. mirre, F. myrrhe, L. myrrha,
   murra, Gr. ?; cf. Ar. murr bitter, also myrrh, Heb. mar
   bitter.]
   A gum resin, usually of a yellowish brown or amber color, of
   an aromatic odor, and a bitter, slightly pungent taste. It is
   valued for its odor and for its medicinal properties. It
   exudes from the bark of a shrub of Abyssinia and Arabia, the
   Commiphora Myrrha (syn. Balsamodendron Myrrha) of the
   family Burseraceae, or from the Commiphora abyssinica.
   The myrrh of the Bible is supposed to have been partly the
   gum above named, and partly the exudation of species of
   Cistus, or rockrose.
   [1913 Webster]

   False myrrh. See the Note under Bdellium.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Commiphora myrrha
    n 1: tree of eastern Africa and Asia yielding myrrh [syn: myrrh
         tree, Commiphora myrrha]