ABOUT ALLAH THE GLORIOUS WORD

Source: Al-Mizan, An Exegesis of the Quran, by al-Allamah as-Sayyid Muhammad Husayn at-Tabata`i, vol. 1, p.26

"Allah" ( الله = the divine name) was originally al-Ilah (الاله ) ; the "I" ( اِ ) ; in the middle was omitted because of frequent use. al-Ilah is derived from alaha ( اله = he worshipped) or from aliha or waliha (الهor وله= he was bewildered). It is on paradigm of al-fi’al (الفعال)in meaning of al-maf’ul (المفعول = object-noun). For example, al-Kitab (الكتاب) means al-Maktub ( المكتوب) = the written); likewise al-Ilah means al-Ma’luh (المألوه) that is, the One who is worshipped, or the One about whom minds are bewildered.
Quite clearly, it has become the proper name of God. It was commonly used in this meaning in Arabic long before the Qur'an was revealed. The fact that even pre-Islamic Arabs used this name for God, may be inferred from the following verses:
And if you should ask them who created them, they would certainly say: "Allah" …. (43:87)
.. . . and they say: "This for Allah " - so they assert - "and this is for our associates". (6:136).
Other divine names may be used as adjectives for this name; for example, "the Beneficent and the Merciful Allah"; also, this name is used as subject of the verbs derived from other divine names; for example, "Allah knew", "Allah had mercy", "Allah gave sustenance" etc. But the word, "Allah", is never used as adjective to any other name, nor is the verb derived from it used to describe other names. It is a clear proof that it is the proper name of God.
The divine existence, in as much as Allah is the God of everything, presupposes that He should have all the attributes of perfection; and, as a result, this name points to all perfect attributes. That is why it is said that the name, "Allah", means "the Person Who is the Essential Being, and Who encompasses all the attributes of perfection". But the fact is that it is the proper name of God and no other meaning (except that related to worship or bewilderment) has been taken into consideration here.