1859, "formation or development of cells," 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." Meaning "enlargement, extension, increase" is from 1920; especially of nuclear weapons (1966).
the proliferation of nuclear weapons
proletarianism
proletariat
prolicide
pro-life
proliferate
proliferation
proliferative
prolific
prolix
prolixity
prologue