Day Star
From BiblePortal Wikipedia
Morrish Bible Dictionary [1]
φωσφόρος The word is from φῶσ and φέρω, 'to bring light.' 2 Peter 1:19 . Prophecy is a light in this dark world respecting things here and judgement. But, in contrast to judgement, the dawn and the day star are a better hope, not seen by those who appear only when the sun is risen, but for saints who look for Christ before He appears.
Holman Bible Dictionary [2]
Isaiah 14:12 2 Peter 1:19 Isaiah 14:12Lucifer
Hastings' Dictionary of the Bible [3]
DAY STAR . See Lucifer.