Star of the morning (or as NASB renders it, bright morning star).
Revelation 22:16 [ NASB ]
“I, Jesus, have sent My angel to testify to you these things for the churches. I am the root and the descendant of David, the bright morning star.”
Many read this and are concerned because the enemy appears to be called a similar title in Isaiah:
Isaiah 14:12 [ NASB ]
“How you have fallen from heaven,O star of the morning, son of the dawn!You have been cut down to the earth,You who have weakened the nations!
The King James version renders this as How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! leaving the phrase Star of the morning as "Lucifer".
But, it is important to understand that in the Isaiah passage, it was used in a somewhat mocking sense to show how far the enemy fell, not as a sober description of the enemy, much less his name. This is a reverse similarity to the mocking Jesus received from onlookers (example: Luke 33:35) at his crucifixion. In the case of the mocking of our Lord, the reality is that He was ( is ) the Christ they mockingly called Him.