The words appetite and hunger are difficult to tell apart a lot of the time. They seem to be used interchangeably. Hunger is the easier term; it's the body's need for energy. Now, if you are hungry and ingest something energy dense, you can satisfy or satiate your hunger but it is likely that you will feel the need for a certain something, that's:
Appetite. The content or make up of what you actually eat, the balance of nutrients both major and minor.You can feel full but still hunger for something else that better fulfils you needs. Calories although important and will see you through if you had no choice, are not enough over the longer term, you need things that contain the balance of nutrients you need.
A craving is often part of that appetite, when it is either unsatisfied, has built up over time, or due to unusual demands made on your body, often in times of growth, your own on in the case of women, growing a baby.