القُبُوْرِ

A word in the Arabic language will either be 1) a verb or 2) a noun or 3) a particle – القُبُوْرِ is a noun

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

القُبُوْرُ is the natural state of this definite noun and it changes to القُبُوْرِ due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

Graves

To bury (the dead)

Surah/Below are the 4 verses in the holy Quran containing the genitive nounالقُبُوْرِ
Verse
22-7
35-22
60-13
100-9Knows he not that when the contents of the graves are poured forthأَفَلَا يَعْلَمُ إِذَا بُعْثِرَ مَا فِي القُبُوْرِ