1. If you ban something, you state officially that it must not be done, shown or used. • The San Jose City Council on Tuesday voted to make their city the largest in the nation to ban most plastic and paper shopping bags. Ban is also a noun. • In a recent Harris poll, 80 percent of participants favored a ban on text-messaging while driving.
2. UN is an abbreviation for United Nations.
'Ban the Bomb' was the slogan of the Campaign for Nuclear Disarmament and became part of the youth culture of the sixties, appearing on T-shirts and banners everywhere.