The French word for God is Dieu. The German word for God is Gott, Hebrew calls him Adonai or Elohim (which is plural, by the way). Every language calls God something different. Even the name of Jesus is Yeshua, which should more accurately be translated "Joshua." Man's finite language is inadequate to name and give glory to God.
Allah is the word for God in the Arabic language. Whether or not the Muslim definition matches the creed in which you believe is an entirely different matter. It's not up to any man to pass judgment on another's religion. All you can do is decide for yourself and allow others the same freedom. Anything less shows a lack of charity and benevolence that, by any estimation, should be qualities of a person professing the Christian faith.