This is the 308th most frequent Russian word.
мире
The Russian word "мире" means "world" in the prepositional case, often translated as "in the world."
Here, "мире" refers to "peace" and is in the prepositional case after the preposition "о."
Я мечтаю о мире и спокойствии.
I dream of peace and tranquility.
In this sentence, "мире" is used in the prepositional case to specify the particular "world" mentioned.
В этом мире есть много добрых людей.
There are many kind people in this world.
The word "мире" is used in the prepositional case to refer to the location "in the world."