AO stands for Adults Only. Titles rated AO have content that should only be played by persons 18 and Older. The AO for Adults Only rating means that, according to the ESRB's official definition, the current version of the game now "should only be played by persons 18 years and older" and "may include.
The ESRB's "Adults Only" ratings symbol The following is a list of video games that have been given the " Adults Only " (AO) rating by the Entertainment Software Rating Board (ESRB), a United States -based organization which rates the content of video games to determine . Interestingly, there’s a ranking above Mature (17+), dubbed Adults Only (18+). This highest ranking is given out only in rare, extreme cases; Sony, Microsoft and Nintendo do not allow AO games on.
Was rated AO for some time while the "Hot Coffee" mod was still in the games code.