The name Allah is not confined to Islam alone; it is also the name by which Arabic-speaking Christians of the oriental churches call upon God. 
Some food for thought for those antagonistic Christians who traverse the cyber and real world spewing out the most vile of insults directed at Allah. Do they not know they are committing blasphemy – even in the eyes of their Arab (and learned) Christian brethren???
 The Concise Encyclopaedia of Islam, Revised Edition, Cyril Glasse, Stacey International, 2001, p42