The general public; people in society at large (used in expressions like 'in public' or 'public health').
公衆の面前で喫煙するのはマナー違反だ。
Smoking in front of the public is bad manners.
駅には公衆電話がまだ設置されている。
There are still public phones installed at the station.
公衆衛生の改善は政府の重要な課題だ。
Improving public health is an important issue for the government.