If someone in authority censors letters or the media, they officially examine them and cut out any information that is regarded as secret.

A censor is a person who has been officially appointed to examine letters or the media and to cut out any parts that are regarded as secret.

If someone in authority censors a book, play, or film, they officially examine it and cut out any parts that are considered to be immoral or inappropriate.

A censor is a person who has been officially appointed to examine plays, films, and books and to cut out any parts that are considered to be immoral.