Lucifer first appeared in the Latin Vulgate. It first appears in Isaiah 14, as the Hebrew helel, which means morning, bright, star and so forth. The Vulgate translators interpreted it as the Devil, but found a surprise when they worked themselves up to the New Testament. A verse in 2 Peter calls Christ "day star" but the Greek word should be translated into Latin as Lucifer. Not wanting to call Jesus and the devil by the same name, they borrowed day star from Revelation.
The devil is thought of as Lucifer today because of the Vulgate, whereas if they had translated it correctly, we would think of Lucifer as Jesus. And the passage in Isaiah as reference to the king of Tyre, as originally intended.