Yours, Etc.: Origins and Uses of 8 Sign-Offs
1690s, as a term in logic, from French synthétique (17c.), from Modern Latin syntheticus, from Greek synthetikos, from synthetos, past participle of syntithenai (see synthesis). From 1874 in reference to products or materials made artificially by chemical synthesis; hence "artificial" (1930).
synthetic syn·thet·ic (sĭn-thět'ĭk)
Relating to or involving synthesis.
Produced by chemical synthesis, especially not of natural origin.