المعنى الاصطلاحي :

One of the layers (levels) of torment in Hellfire.

الشرح المختصر :

"Darak" (A layer in Hellfire) is one of the layers of Hellfire. It is the opposite of "daraj", because "daraj" refers to ascending levels whereas "darak" refers to descending levels. For this reason, "darajāt" is used to refer to the levels of Paradise while "darakāt" is used to refer to the levels of Hellfire. The deeper the fire is, the hotter it becomes, and the more intense its flames are; and the more disbelieving and misguided a person is, the severer the punishment he will receive. The hypocrites will receive the biggest portion of punishment, that is why they will be in the lowest bottom of the Fire (ad-darak al-asfal). It was reported that Ibn Mas‘ood, may Allah be pleased with him, said: "Ad-darak al-asfal" are coffins of iron to which they will be chained in the lowest depth of the Hellfire."

التعريف اللغوي المختصر :

"Dark": the rock-bottom, the lowest possible level of something, the bottom of everything that is deep such as the sea and the like. "Dark" is one of the levels of Hell (adrāk) which differ in their degree of hotness. Other meanings: catching up with, reaching something.