propaganda: [18] English gets the word propaganda from the term Propaganda Fide, the name of a Roman Catholic organization charged with the spreading of the gospel. This meant literally ‘propagating the faith’, prōpāgānda being the feminine gerundive of Latin prōpāgāre, source of English propagate [16]. Originally prōpāgāre was a botanical verb, as its English descendant remains, only secondarily broadening out metaphorically to ‘extend, spread’.
It was derived from the noun prōpāgo ‘cutting, scion’, which in turn was formed from the prefix prō- ‘forth’ and the base *pāg- ‘fix’ (source of English pagan, page, pale ‘stake’, etc). => pagan, page, pale, propagate
propaganda (n.)
1718, "committee of cardinals in charge of Catholic missionary work," short for Congregatio de Propaganda Fide "congregation for propagating the faith," a committee of cardinals established 1622 by Gregory XV to supervise foreign missions. The word is properly the ablative fem. gerundive of Latin propagare (see propagation). Hence, "any movement to propagate some practice or ideology" (1790). Modern political sense dates from World War I, not originally pejorative. Meaning "material or information propagated to advance a cause, etc." is from 1929.