رَبِّ الْعَالَمِينَ

Salaamun Alaikum.

Dr Hany translated رَبِّ الْعَالَمِينَ as The Lord of all the realms. I didn't quite understand this. Also, Dr Bassam Saeh in his book said that this expression is not found in any 7th century Arab poets literature. This word did not even exist. So I was quite curious about this expression.

I came across Surah 26:23-24,
 قَالَ فِرۡعَوۡنُ وَمَا رَبُّ ٱلۡعَٰلَمِينَ 
 Said Pharaoh, "And what is رَبِّ الْعَالَمِينَ?" 

 قَالَ رَبُّ ٱلسَّمَٰوَٰتِ وَٱلۡأَرۡضِ وَمَا بَيۡنَهُمَآۖ إِن كُنتُم مُّوقِنِينَ 
 [Musa] said, "The Lord of the layers of understanding and the scriptural text and that between them, if you should be convinced." 

These Ayaath seem to give the definition and it is an Abrahamic Locution! This expression occurs in the Quran 43 times. Very excited to study them all. Again another evidence that Quran has nothing to do with 7th century Arab poet's language. Please correct me if I am wrong.