What is the difference if any between a nutritionist and dietitian?

A dietitian is someone who has at least a 4 year degree in the field of dietetics or nutrition. They are also required to complete an internship and pass certain tests. A nutritionist is a more broad term that can cover any array of persons who have received a degree, or even people who just have learned a large amount about nutrition. So basically, a dietitian typically has more schooling and knowledge than a nutritionist.