Chef and cook are most times used interchangeably, that you might be forced to think they are entirely the same. A chef in a more profound sense is not the same as a cook. However, both words are referring to someone who prepares food. A chef can be regarded as someone who is professionally trained and makes meals for living in a more organized setting. A cook, on the other hand, is just anyone who prepares foods; it can be anybody in a family. Cook can be used to refer to someone who manages the kitchen and the kitchen staff.
A chef, on the other hand, can be regarded as a head cook in a restaurant, and by this, he has so many other cooks working under him. Most times, a cook might be employed to be doing some additional works apart from cooking. But a chef, since he's professionally trained for the job, cannot be employed for that kind of work