caoutchouc

from The Century Dictionary.

• noun An elastic gummy substance, the inspissated milky juice of various tropical trees belonging to the natural orders Apocynaceæ, Urticaceæ, and Euphorbiaceæ; india-rubber (which see).
• noun Products more or less resembling caoutchouc are obtained by the application of the vulcanizing process to colza and other oils, and are employed to mix with or partly replace real india-rubber. A substance which seems to be identical with natural caoutchouc has been obtained in the scientific laboratory by polymerization of isoprene, a hydrocarbon derived from turpentine; but the process has not become commercially practical.

from the GNU version of the Collaborative International Dictionary of English.

• noun A tenacious, elastic, gummy substance obtained from the milky sap of several plants of tropical South America (esp. the euphorbiaceous tree Siphonia elastica or Hevea caoutchouc), Asia, and Africa. Being impermeable to liquids and gases, and not readly affected by exposure to air, acids, and alkalies, it is used, especially when vulcanized, for many purposes in the arts and in manufactures. Also called India rubber (because it was first brought from India, and was formerly used chiefly for erasing pencil marks) and gum elastic. See vulcanization.
• noun See under Mineral.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun latex; natural rubber

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products