Is Borgu an Empire or a Kingdom?

An Empire is a large multi-ethnic state ruled by a central authority,often through military force. It could consist of multiple provinces or political entities, but they must all be subservient to the emperor. In other hand, a Kingdom is a country ruled by either a king or queen. It is usually ethnically homogeneous with a common language, history, culture, and sense of identity. There should be consensus among the people that the monarchy has a dentist jure right to rule over them.

So therefore, Borgu could be termed as an Empire, because it has satisfied the requirement of the above definition of an Empire. Borgu would be considered an an Empire and not as a Kingdom.