Enthalpy of Fusion (Melting)
Enthalpy of Fusion is defined as the heat that is absorbed when the melting occurs at constant pressure.  If the substance freezes, the reaction is reversed, and an equal amount of heat is given off to the surroundings; i.e., ΔHfreez = - ΔHfus
Melting (fusion) is an endothermic process
solid
liquid