سِيْنِيْنَ

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

سِيْنُوْنَ is the natural, nominative (مَرْفُوْعٌ) state of this definite noun and it changes to its genitive (مَجْرُوْرٌ) state سِيْنِيْنَ 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

Mount Sinai, Mount where Moses received the Divine Commandments

مَعْرِفَةٌمُفْرَدٌمُذَكَّرٌمَجْرُوْرٌس ي نبَاب ضَرَبَفِعْلِيْنَسَانَ يَسِيْنُاسْمٌالْاِسْمُ الْعَلَمُ
DefiniteSingularMasculineGenitiveRootSinaiPatternضNounProper noun
مَمْنُوْعٌ مِنَ الصَّرْفِ
Diptote
Verse/Below is the only verse in the holy Quran containing the proper nounسِيْنِيْنَ
Ayat
95-2and the Mount of Sinaiوَطُوْرِ سِيْنِيْنَ