What do you mean by leeward and windward sides of mountains?

The windward side of a mountain faces the incoming wind, while the leeward side is sheltered from it.

As moist air rises along the windward side, it cools and condenses to form clouds and rain. By the time the air crosses to the leeward side, it becomes dry, creating a rain shadow region. 

For example, the western slopes of the Western Ghats receive heavy rain, while the eastern slopes remain relatively dry. The windward side thus supports lush vegetation, and the leeward side often has drier climates. 

This concept explains regional weather patterns and agriculture differences in hilly areas.