Censorship is a word of many meanings. In its broadest sense it refers to suppression of information, ideas, or artistic expression by anyone, whether government officials, church authorities, private pressure groups, or speakers, writers, and artists themselves. It may take place at any point in time, whether before an utterance occurs, prior to its widespread circulation, or by punishment of communicators after dissemination of their messages, so as to deter others from like expression.
In its narrower, more legalistic sense, censorship means only the prevention by official government action of the circulation of messages already produced. Thus writers who "censor" themselves before putting words on paper, for fear of failing to sell their work, are not engaging in censorship in this narrower sense, nor are those who boycott sponsors of disliked television shows."