What do the movie ratings mean? ...

Art is likened to a feather that tickles the inner depths of our minds. However, not everyone is ready to be tickled by these "triggers". Art has many levels and it usually requires a certain level of maturity to fully appreciate and understand the messages it conveys. Movies/films being a form of art also has the same effects and as such, a classification board is assigned to review and designate a "movie ratings system" for all movies that are to be shown within their area.

The parameters on movie classification change over time, oftentimes based on a particular period's range of conservativeness and/or liberalism. For example in the 60s and early 70s, movies that show cigarette smoking and gambling such as texas holdem or other casino scenes are given R ratings; nowadays most movie review boards are more lenient. Today's ratings are based on the following:

G General Audiences: All ages admitted.

PG Parental Guidance Suggested: Some material may not be suitable for children.

PG-13 Parents Strongly Cautioned: Some material may be inappropriate for children under 13.

R Restricted: Under 17 requires accompanying parent or adult guardian.

NC-17 No One 17 and Under Admitted

Wikipedia article: "MPAA film rating system"

How is the NC-17 rating determined? More information on movie ratings is available at the Motion Picture Association of America.