In Britain, films that are labelled ~ are not considered suitable for younger children to see without an adult being with them. ~ is an abbreviation for ‘parental guidance’.
PG
Meaning of PG in English
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012