Question

What is latent heat of fusion

Answer 1

the latent heat of fusion is the amount of heat required change a unit mass of substance from it's solid state to it's liquid state at a constant temperature.
hey friend,
I think if u need a proper definition u might use this one.

Answer 2

as Latent means hidden and fusion means Changing of a solid into liquid so latent heat of fusion means the amount of heat given to a substance which is used to change the state of that substance from liquid to solid not to increase the temperature is the latent heat of fusion