Tasneem means a heavenly fountain.
Tasneem is the name of one of the most honorable drinks of the inhabitants of the Paradise. It is poured on them form the heights.
Tasneem is the name of a fountain in Jannahh (Paradise) whose drink is superior to the purest of wines. Its nectar will only be drunk by those nearest to Allah Ta’ala. Literally means “rich and elevated”.
Tasneem is the name of a spring in Paradise as stated in the Glorious Quran Chapter 83 Surah Mutaffefeen verse 27 & 28:
27 With it will be (given) a mixture of Tasneem;
28 A spring from (the waters), whereof drink those Nearest to Allah.