There is no Hebrew word for Lucifer. In Isaiah 14:21 the term "Helal ben Shaḥar" means "the brilliant one, son of the morning". In the Septuagint, this became Φωσφόρος (phosophoros) and is translated into English via Latin as Lucifer. Neither the OT nor the NT actually mentions 'Lucifer' or its Greek and Hebrew equivalents as the name of an archangel.
So strictly speaking the Bible does not say that the archangel Lucifer is "son of the dawn." Rather "son of the dawn" (ben Shahar) is an epithet describing "Helal." The passage in Isaiah 14 addresses the historical the King of Babylon, predicting his utter degradation.
4 you will take up this taunt-song against the king of Babylon - How the oppressor has come to an end! how the turmoil has ended!... 9 Below, Sheol is all astir preparing for your coming; Awakening the shades to greet you... you are just like us! 11 Down to Sheol your pomp is brought, the sound of your harps. Maggots are the couch beneath you, worms your blanket 12 How you have fallen from the heavens, O Morning Star, son of the dawn!
Conclusion: The idea that Isaiah 14 is speaking about the archangel Lucifer is a product of later theology. The Bible itself uses the term "Helal ben Shaḥar" to refer to the King of Babylon, a man who would die like any other man. This does not mean that either Christian or Islamic theologians are mistaken, only that the Bible itself does not speak of an archangel by the name in question.