Really, many people claim that Allah is just an Arabian term for God. Actually, it is. But
it's not that simple, see? The dictionaries are all about different meanings. So: Common meaning in this time in non-arabic countries is that it reffers to the Moslim God, who IS different - at least the moslim's view is really different from Christians' and Jews'!
Christians believe, that Jesus is God, Jews don't take Him at all, Moslims don't take him as God but just as one of the prophets. So - the Christians' God is not the same as Moslims' - He is Jesus, who sacrificed and
resurrected - I am not Jew but I think their view of God is really different, too.