Propaganda is information that is not objective and is used primarily to influence an audience and further an agenda, often by presenting facts selectively to encourage a particular synthesis or perception, or using loaded language to produce an emotional rather than a rational response to the information that is presented. Propaganda is often associated with material prepared by governments, but activist groups, companies and the media can also produce propaganda. 

In the twentieth century, the term propaganda has been associated with a manipulative approach, but propaganda historically was a neutral descriptive term. A wide range of materials and media are used for conveying propaganda messages, which changed as new technologies were invented, including paintings, cartoons, posters, pamphlets, films, radio shows, TV shows, and websites. 

In a 1929 literary debate with Edward Bernays, Everett Dean Martin argues that, “Propaganda is making puppets of us. We are moved by hidden strings which the propagandist manipulates.” 

"Propaganda" is a modern Latin word, the gerundive form of "propagare", meaning "to spread" or "to propagate", thus "propaganda" means "that which is to be propagated". Originally this word derived from a new administrative body of the Catholic church (congregation) created in 1622, called the "Congregatio de Propaganda Fide" ("Congregation for Propagating the Faith"), or informally simply "Propaganda". Its activity was aimed at "propagating" the Catholic faith in non-Catholic countries.
Who was he debating with?
Edward Bernays