Dear Student,
The amount of heat energy required to change 1 kg of a solid in to its liquid state at its melting point is known as the latent heat of fusion, whereas the latent heat of vaporisation is defined as the amount of heat energy required to convert 1 kg of a liquid in to its vapour state at its boiling point.
latent heat of fusion and vaporisations are a measure of strength of inter particle forces in solid and liquid state respectively
Regards.