The melting point of ice is 273.16 kelvin. what does it mean ?

Ice is solid at 0°C i.e., 273° K. The molecules of ice are tightly packed. These molecules have to overcome the force of attraction with which they are held and hence they gain this heat from the surrounding but the temperature remains the same as their energy is used to overcome the force of attraction between the particles.

For understanding it easily u can convert it to Celsius scale by subtracting 273 from the kelvin temprature