This text is taken from http://www.saheefah.org/
The name Allah is originated from “ilaah”. In the aayah above, He said “there is no? ilaah along with Him”. There is no ilaah along with Him meaning there is no one that should be worshipped with Him. Also, there is no other Creator, Sustainer, Lawgiver, and so on. Whatever does not have these Names and Attributes cannot be an ilaah even if it is worshipped; it is only another creation.
Its root is “aliha ya’lahu”, which means to be bewildered. When the slave of Allah realizes His Greatness, Majesty, and other attributes, he will be the most unlikely to turn his heart towards anyone else. [Ibnul Atheer]
The root of ilaah is “wilaah”, in which the?waw was changed to a hamza as in some other Arabic words. The meaning of wilaah is that all of the creation turn to Him for their needs, to keep away harm, and retreat to Him when frightened.
•All of the following words: ilaaha, ulooha, and uloohiyya mean ‘ibaada, i.e, to worship. Regarding the following aayah:
Wilt thou suffer Moses and his people to make mischief in the land, and flout thee and thy gods (aalihatak)? [A'raaf 7:127]
Abdullah Ibn Abbaas RA used to recite the aayah as, “and flout thee and thy worship (ilaahatak),” because Pharoah was actually worshipped. For this reason, the action is referred to in this recitation as “ilaaha” (Of course, the first recitation listed is the most common and famous recitation) [Ibn Seedah].
An Additional proof is the statement of Pharoah: I know not that ye have a god (ilaah) other than me [Qasas 28:38]
The original form of the Name Allah is “al-ilaah”. This was stated by the grammarian and linguist Seebawayh and most of his students. [Ibnul Qayyim]. The hamza was dropped due to the common usage in the language, thereby the name became Allah. [Ibn Barree]
Please note: Repeating the name Allah by itself is not something found in the sharia. Rather, the remembrances [adhkaar] that are found in the sharia mention the name along with other words of praise and glory.