mid-15c., propagacioun, "the causing of plants or animals to reproduce; reproduction; act or fact of begetting or being begotten," from Old French propagacion "offshoot, offspring" (13c.) and directly from Latin propagationem (nominative propagatio) "a propagation, extension, enlargement," noun of action from past-participle stem of propagare "set forward, extend, spread, increase; multiply plants by layers, breed," from propago (genitive propaginis) "that which propagates, offspring," from pro "forth" (see pro-) + -pag, from PIE root *pag- "to fasten," source of pangere "to fasten" (see pact). Sense of "spreading, diffusion, extension" (of light, sound, etc.) is from 1650s.
updated on December 11, 2020