This is the 1374th most frequent Japanese word.
世
"世" means "world," "generation," or "society."
In this sentence, '世' refers to 'this world' or 'the realm of human existence', emphasizing the physical world we live in.
この世には多くの不思議があります。
There are many wonders in this world.
Here, '世' is used to represent 'society' or 'the general affairs of people', indicating the ever-evolving nature of collective human life.
世の中は常に変化していきます。
The society constantly undergoes changes.
In this case, '世' is connected to '世間' (public or people in society), stressing the opinions or concerns among the members of society.