On lowering the temperature, a liquid turns into a solid. What is this process called?
Freezing
When the temperature is lowered, a liquid turns into a solid. This is called freezing.
For example, when you try to make ice using your ice trays, you first fill water in the ice trays then you put it in the freezer in your refrigerator right? After a while you have solid water, which we call ice, in the form of nice cubes you can play with!