Barzakh (Arabic: برزخ, from Persian barzakh, "barrier, partition") is an Arabic word meaning "obstacle", "hindrance", "separation", or "barrier".
The Arabic word barzakh is derived from the Persian barzakh, "barrier, partition", which is in its turn traced back to the combination barz+ax(v) ("high existence"), analogous to the Persian word for hell, dūzakh < dūžax(v) ("evil existence").
In The Quran
(23:100) "So that I may do good in what I have left behind." No, it is but a word he is speaking. There is a barrier (Arab. بَرْزَخٌ, barzakhun) to prevent them from going back until the day they are all resurrected.
(25:53) He is the One who merges the two bodies of water. This is fresh and palatable and this is salty and bitter. He made between them a partition and an inviolable barrier (Arab. بَرْزَخًا, barzakhan).