proliferation (n.)

1859, "formation or development of cells by budding or division," from French prolifération, from prolifère "producing offspring," from Latin proles "offspring" (see prolific) + ferre "to bear, carry" (from PIE root *bher- (1) "to carry," also "to bear children"). The meaning "enlargement, extension, increase in number" is from 1920; especially of nuclear weapons by 1960 in the jargon of the U.S. State Department.