What is meant by latent heat or latent heat of fusion? How will the state of matter transform if latent heat is given off?

The amount of heat needed to modify the state of unit mass of the body from solid to liquid or from liquid to gas without resulting in any change in temperature is called latent heat. When the latent heat is given off the body in liquid state, it will convert to solid state and the body in vapour state will transform to liquid state. This means the internal energy of the matter is reduced when latent heat is given off.