There is no question that the word "Allah" is the Arabic word for God. We use it in the Church. But there's speculation as to why Mohammed used the crescent moon as a symbol of Islam, which also connects the origin of the word "Allah" to a Hindu moon goddess.
God bless (Allah yi barik ).
There is no "Hindu moon goddess." There is a Hindu God associated with the moon named Chandra which has nothing to do with the name "Allah" at all.
I think the speculation that connects "Allah" to a Hindu lunar deity, comes from the existence of a royal dynasty in ancient India, called the "Aila" dynasty, which was part of the Lunar (as opposed to Solar) dynasty. (The Buddha hailed from the Solar dynasty, as did Rama; Krishna, though, was of the Lunar dynasty.) The Aila dynasty was so-called because they descended from an individual named "Ila" (which looks sort of like it could be connected to the Semitic root "El"). Ila is also called "Ida".
In any event, it shouldn't be surprising that Allah might have some lunar connection, since the Sinai of "Mt. Sinai" might be related to the lunar deity of the Babylonians, Sin. One might predict that various Semitic ideas of deity were related, in the past, to the moon.