Motion Picture Association of America. the Motion Picture Association of America a US organization whose job is to watch new films and decide whether children or young people will be allowed to see them. Each film is given a rating, which shows for example that a film can be shown to anyone (G), or can be seen by children if an adult goes with them (PG). A film that has an 'X' rating probably has a lot of sex and violence in it, so can only be seen by people who are at least 18 years old. There is a similar organization in the UK called the British Board of Film Classification