Al-Ghaib: literally means a thing not seen. But this word includes vast meanings: Belief in Allah, Angels, Holy Books, Allah's Messengers, Day of Resurrection and Al-Qadar (Divine Preordainments). It also includes what Allah and His Messenger (p) informed about the knowledge of the matters of past, present and future, e.g., news about the creation of the heavens and earth, botanical and zoological life, the news about the nations of the past, and about Paradise and Hell.
[From the explanatory section in the Interpretation of the Meanings of the Noble Quran in the English Language]
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