The Collaborative International Dictionary of English v.0.48:

Gutta-percha \Gut"ta-per`cha\, n. [Malay gutah gum + pertja the
   tree from which is it procured.]
   A concrete juice produced by various trees found in the
   Malayan archipelago, especially by the Isonandra Gutta,
   syn. Dichopsis Gutta. It becomes soft, and unpressible at
   the tamperature of boiling water, and, on cooling, retains
   its new shape. It dissolves in oils and ethers, but not in
   water. In many of its properties it resembles caoutchouc, and
   it is extensively used for many economical purposes. The
   Mimusops globosa of Guiana also yields this material.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gutta-percha
    n 1: a whitish rubber derived from the coagulated milky latex of
         gutta-percha trees; used for insulation of electrical
         cables