1. Any regime or context in which the content of what is publically expressed, exhibited, published, broadcast, or otherwise distributed is regulated or in which the circulation of information is controlled. The official grounds for such control at a national level are variously political (e.g. national security), moral (e.g. likelihood of causing offence or moral harm, especially in relation to issues of obscenity), social (e.g. whether violent content might have harmful effects on behaviour), or religious (e.g. blasphemy, heresy). Some rulings may be merely to avoid embarrassment (especially for governments).
2. A regulatory system for vetting, editing, and prohibiting particular forms of public expression, presided over by a censor: an official given a mandate by a governmental, legislative, or commercial body to review specific kinds of material according to pre-defined criteria. Criteria relating to public attitudes—notably on issues of ‘taste and decency’—can quickly become out-of-step.
3. The practice and process of suppression or any particular instance of this. This may involve the partial or total suppression of any text or the entire output of an individual or organization on a limited or permanent basis.
4. Self-censorship is self-regulation by an individual author or publisher, or by ‘the industry’. Media industries frequently remind their members that if they do not regulate themselves they will be regulated by the state. Self-censorship on the individual level includes the internal regulation of what one decides to express publically, often attributable to conformism.
5. In Freudian psychoanalytical theory, the suppression of unconscious desires that is reflected in the oblique symbolism of dreams: see displacement.