is not used for Allah ta'ala. It is used for the Prophet and it means peace and blessings of Allah be upon him.
You may have noticed that I've used "ta'ala" (تعالیٰ in Arabic) after the name of Allah. It means the most high. We can also say "subhanahu wa ta'ala" (سبحانه وتعالى in Arabic) for Allah and it means the most glorified and the most high.