What is defined as the temperature at which a substance changes from a liquid to a solid?

The freezing point of a substance is defined as the temperature at which it transitions from a liquid state to a solid state. At this specific temperature, the kinetic energy of the molecules decreases, allowing them to arrange into a fixed structure, thus forming a solid. This process is essential for understanding various physical changes in substances and is a fundamental concept in thermodynamics.

In contrast, the melting point refers to the temperature at which a solid changes into a liquid, the boiling point is the temperature at which a liquid turns into a gas, and the sublimation point is the temperature at which a solid changes directly to a gas without becoming a liquid first. These definitions highlight different phase changes, with the freezing point specifically addressing the solidification process.