What is meant by "Umm al-Kitab" (the Mother of the Book) mentioned in Surat Az-Zukhruf, and is it the same as "Al-Lawh Al-Mahfuz" (the Preserved Tablet) mentioned in Surat Al-Buruj, or is there a difference between them?

"Umm al-Kitab" (Mother of the Book) in Surat Az-Zukhruf means the Preserved Tablet mentioned in Surat Al-Buruj, and they are synonymous. Ibn Kathir said: "And indeed, it (meaning the Qur'an) is in Umm al-Kitab, meaning the Preserved Tablet, as stated by Ibn Abbas and Mujahid." Al-Shawkani said: "Umm al-Kitab is the origin of the Book, and the Qur'an is affirmed with Allah in the Preserved Tablet, as He said: 'But it is a glorious Qur'an, in a Preserved Tablet.'"