PG on a film means Parental Guidance. It is a note to families: this film is not only for little children. There may be a scare, a fight, or some rude language — not a flood of it, but enough that a parent might want to think first, or sit with a younger child. It is not a ban. Children can still watch. It just says: parent, you decide. The letters come from the US and UK film-rating systems; the small print is not identical in each country, and what feels 'a bit much' for a child has shifted over the years. People say 'a PG film' or 'it's rated PG'. Though actually, PG is a busy pair of letters in English — they can mean other things in other files — but on a poster or a streaming page, this is the film-guide sense.