The seven ratings used by the television industry are divided into two groups. Three apply solely to children's programming: TV-Y, appropriate for all children; TV-Y7, which are shows intended for children age 7 and older; and TV-Y7-FV, which is still aimed at kids, but contains fantasy violence which may be more intense than other kinds of children's programming. Superhero shows such as "Batman" often receive this rating.
The remaining four ratings apply to shows not aimed specifically at children; they're loosely patterned after the ratings used by the movie industry and apply the same criteria. TV-G is a show acceptable to all audiences, such as a nature documentary. TV--PG shows contain some adult material which parents might find objectionable to the very young, such as mild violence or sexual innuendo. TV-14 shows contain material that most parents would find objectionable for children under 14. Finally, TV-MA programs are intended for adults only, and considered unsuitable for children under the age of 17.
In addition to the seven general ratings, every television show may contain a series of one-letter content labels used to specify their content. "V" means a show which contains violence, ranging from a fistfight to a gunfight to a graphic murder. The intensity of the violence is indicated by the show's general rating: a TV-MA program may depict a brutal murder, while a TV-PG show may contain a more benign barroom brawl.
Two specific content labels inform parents about sexual content. "S" indicates a sexual situation, ranging from inferred lovemaking to overt nudity. "D" indicates dialogue with suggestive or overtly sexual content (which usually means characters talking about sex). The latter is obviously more mild than the former, though specifics depend on the general rating to which the content label is attached.
The "L" content label refers to coarse or vulgar language, including but not limited to "the seven words you can never say on television." National networks and local television stations usually refrain from using crude language in their programs, but some cable stations---particularly premium cable stations such as HBO and Showtime---will broadcast shows with harsh language.