In keeping kosher, it is necessary to keep all dairy and meat foods completely separate — which, unless one is vegetarian, necessitates separate sets of dishes and cooking utensils.
Pareve foods, however, may be mixed in and served with either category of food since these foods are neither milk nor meat.
Dairy, often described with the Yiddish word, these are foods, such as cheese, milk, yogurt, ice cream, etc.
Meat, often referred to with the Yiddish word fleischig, this includes all kosher animals and fowl slaughtered in the prescribed manner, and their derivative products.
Pareve, a Yiddish word meaning “neutral,” this describes foods that are neither dairy nor meat, such as eggs and fish, tofu, nuts, seeds, fruits and vegetables, and the like, provided they are not prepared with any milk or meat products.
Whether a particular food is considered kosher or not usually has to do with whether any substance or product used in its manufacture was derived from a non-kosher animal or even an animal that is kosher but was not slaughtered in the prescribed manner.
Rabbinic supervision of the production of food (a practice called hashgacha) enables it to carry a “seal of approval” (but no, it is not “blessed by a rabbi”).