The Holy Quran says: “The most beautiful names belong to Allah: So call on Him by them”[1] There are many names for Allah (swt) and most of them are mentioned in the dua of Jawshan Kabir. Each of these names points to one of the virtues that Allah (swt) possesses; a virtue that is not mixed with deficiency or nothingness (and in the case of a virtue being mixed with deficiency or nothingness, in order to be able to attribute it to Allah (swt), one should first separate it from any deficiency and then attribute it to Him). Sheikh Jamaluddin Amad ibn Fahd says in his book of Uddatul-Da’i on behalf of Imam Ridha (as) that the imam (as) heard from his father who had heard from his father all the way to Imam Ali (as) that he said: “Indeed there are 99 names for Allah.”[2] Also, the Quran mentions various names and attributes for Allah.[3] The supplication of Jawshan Kabir contains approximately a thousand names and attributes.[4] Explaining the meaning of each name and attribute is impossible via this article but you may refer to some books, tafasir or even translations of the Quran to get explanations on the names you desire to know more about.
[1] A’raf:80.
[2] Ahmad ibn Fahd Hilli, Uddatul-Da’i, pg. 337.
[3] http://www.tebyan.net/index.aspx?pid=4897.
[4] See: Mafatihul-Jinan (translation of Jowshan Kabir).