The term 'OOH' is an acronym for 'Out of Home, ' which is a type of advertising that is used outside of the home, such as billboards, bus stops, and other public spaces. 'AAH' stands for 'At-Home, ' which is a type of advertising that is used inside the home, such as television, radio, and print media. Together, these two terms refer to the two main types of advertising used by businesses to reach their target audiences.