Latex is a stable dispersion (emulsion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well.
Latex as found in nature is a milky fluid found in 10% of all flowering plants (angiosperms). It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins, and gums that coagulate on exposure to air. It is usually exuded after tissue injury. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Since the 17th century, latex has been used as a term for the fluid substance in plants, deriving from the Latin word for "liquid." It serves mainly as defense against herbivorous insects. Latex is not to be confused with plant sap; it is a distinct substance, separately produced, and with separate functions.
The word latex is also used to refer to natural latex rubber, particularly non-vulcanized rubber. Such is the case in products like latex gloves, latex condoms and latex clothing.
Originally, the name given to latex by indigenous Equator tribes who cultivated the rubber tree, Hevea brasiliensis, was "caoutchouc", from the words caa ('tear') and ochu ('tree'), because of the way it is collected.