ASSUR WAS a name that referred to Assyria, the capital city of Assyria, and the chief deity of Assyria. Knowing which was which means relying on the context in which it's used. 

In Derek's book The Second Coming of Saturn, he shared research, showing that the word used by the prophet Isaiah for idols, ellilim, derives from the Akkadian name for Assur, Elllil (also known as Enlil, El, Dagon, Molech, Kronos, and Saturn, among others). These idols, then, were spirit beings—underworld spirits equivalent to the Rephaim, or malakim, as they were known at the ancient Amorite kingdoms of Ebla and Mari. 

In short, we believe chapter 10 of Isaiah is a polemic against the entity called Assur, whom we believe is Shemihazah, the leader of the rebellious sons of God in chapter 6 of the book of Genesis. We will see him again in Isaiah 14 as "Lucifer."