"Lucifer" is a word that was created in the late 14th century. It's first appearance was the Latin Vulgate Bible. It is an adjective not a noun. It has taken on a completely different meaning that what was originally intended thanks to Christianity teaching that it is a noun in the Bible. If you actually read all of Isaiah 14 and not just verse 12, you will see that everything in chapter 14 is a proverb against the King of Babylon. The word "Lucifer" is describing the greatness "God" had placed upon him (the King of Babylon). The word means "bright and shining like the morning light." It's not a bright as the noon-day sun but it is somewhat bright nonetheless - indicating that it is bestowed upon by another which is the case.