In the Quran, Allah uses the names Shaytan and Iblis precisely and consistently for specific contextual reasons.
Shaytan, which comes form the Hebrew word “sattan,” meaning adversary, is used whenever Allah SWT is describing the devil’s enmity and animosity towards humanity. For example:
إِنَّ الشَّيْطَانَ لِلْإِنْسَانِ عَدُوٌّ مُبِينٌ
Indeed Shaytan is a clear enemy to man
Iblis, on the other hand, comes from the Greek word “diablos,” which comes from the root “diaballo,” which means to throw someone or to make someone fall.
We find the word Iblis 11 times in the Quran. 10 of those instances relate to his arrogant exchange with Allah in Paradise which leads to him being thrown out of it, and falling out of the mercy of Allah. Here’s an example of Iblis being used in this context:
وَإِذْ قُلْنَا لِلْمَلَائِكَةِ اسْجُدُوا لِآدَمَ فَسَجَدُوا إِلَّا إِبْلِيسَ أَبَىٰ وَاسْتَكْبَرَ
And when We told the angels: “Prostrate yourselves before Adam!” – they all prostrated themselves, except Iblis, who refused and was arrogant…
However, the 11th usage of the word Iblis doesn’t appear to be consistent with the placement of the name in the other 10 ayaat, until, that is, you read the context.
فَكُبْكِبُوا فِيهَا هُمْ وَالْغَاوُونَ وَجُنُودُ إِبْلِيسَ أَجْمَعُونَ
Then they will be thrown into the Fire, they and those who misled them, and the armies of Iblis all together.
This usage aligns perfectly with the Greek root of Iblis, which means to throw someone.
Of all the places where the Devil is mentioned in the Quran, he’s called by a name that originates from a Greek word that means “to throw,” only in the verses that discuss him being thrown out of paradise, and in the single verse that talks about him being thrown into hell. Coincidence?