the world is at peace; peaceful world
A set phrase meaning that the world is calm and peaceful, often used in a literary or formal context. The expression evokes an image of calm seas across the four directions.
I wish for a world at peace.
The expression is composed of 四海 (four seas, i.e., the whole world) and 波静か (calm waves). The exact historical origin is uncertain, but it is a classical phrase used to describe a peaceful world.