The term for the temperature at which a solid turns into a liquid is called melting point. The melting point is a specific temperature for each substance at which it transitions from a solid state to a liquid state due to increased molecular movement. At this temperature, the thermal energy overcomes the forces holding the molecules in a fixed position, allowing them to move freely. The melting point can vary with factors such as pressure and purity of the substance. Knowing the melting point is crucial for applications in chemistry, materials science, and engineering.