Bulghur, Bulgur, bulgur wheat a.k.a. buckwheat.......all are the same thing. They are a primitive grain used as a food source. Bulgur wheat is highly nutritious and tasty as well as healthful.
Buckwheat or bulgur wheat refers to a variety of plants in the dicot family Polygonaceae: the Eurasian genus Fagopyrum, the North American genus Eriogonum, and the Northern Hemisphere genus Fallopia. Either of the latter two may be referred to as "wild buckwheat". Despite the name, they are not related to wheat, and are not cereals or grasses.
Gruel is a food preparation consisting of some type of cereal—oat, wheat or rye flour, or also rice—boiled in water or milk. It is a thinner version of porridge that may be more often drunk than eaten and need not even be cooked. Historically, gruel, often made from millet or barley, or in hard times of chestnut flour and even the less tannic acorns of some oaks, has been the staple of the human diet, especially that of the peasantry. The importance of gruel as a form of sustenance is especially noted for invalids[1] and recently weaned children.