It means that Qur’an mentioned scientific information extensively that even the scientists discovered it after hundreds years. For instance, the Holy Qur’an mentioned in An Noor Surah that the seabed is very dark, this fact has been discovered in twentieth century. “Or [they are] like darknesses within an unfathomable sea which is covered by waves, upon which are waves, over which are clouds – darknesses, some of them upon others. When one puts out his hand [therein], he can hardly see it. And he to whom Allah has not granted light – for him there is no light”. {Verse 40}
Another example of the scientific miraculousness of the Holy Qur’an appeared in this Verse “Ye shall surely travel from stage to stage.” {Surah Al-Inshiqaq. Verse 19}. Allah the Almighty assures that people are going to ascend and go into space, as we see the development of space exploration in the twenty century and the current century.
If you notice Allah’s saying in Qur’an “The example of those who take allies other than Allah is like that of the spider who takes a home. And indeed, the weakest of homes is the home of the spider, if they only knew.” {Al-Ankabut Surah. Verse 41}, as a reader you will find “spider who takes a home” in the Arabic Verse, it is mentioned that the female spider itself builds its home not the male spider. “مَثَلُ الَّذِينَ اتَّخَذُوا مِنْ دُونِ اللَّهِ أَوْلِيَاءَ كَمَثَلِ الْعَنْكَبُوتِ اتَّخَذَتْ بَيْتًا وَإِنَّ أَوْهَنَ الْبُيُوتِ لَبَيْتُ الْعَنْكَبُوتِ لَوْ كَانُوا يَعْلَمُونَ”. That because the spider {female} holds glands in its body that enable her to weave her home. This scientific fact was not discovered at the time of the descent of the Quran.
Another example, Allah, the creator, explains how the rain happens; hot air loaded with water vapor rises, so clouds are formed, then rain or hail falls.
“Do you not see that Allah drives clouds? Then He brings them together, then He makes them into a mass, and you see the rain emerge from within it. And He sends down from the sky, mountains [of clouds] within which is hail, and He strikes with it whom He wills and averts it from whom He wills. The flash of its lightening almost takes away the eyesight.”