عَيْنٍ

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

عَيْنٌ is the natural state of this indefinite noun and it becomes عَيْنٍ 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

Eye; Look; Hole; But of a tree; Spy; Middle letter of a trilateral word; Spring of water; Chief; Personage of a place

To hurt in the eye, smite anyone with the evil eye, flow tears, become a spy

النَّكِرَةُمُفْرَدٌمُؤَنَّثٌمَجْرُوْرٌع ي نبَاب نَصَرَفَعْلٌعَانَ يَعِيْنُاسْمٌاِسْمُ الجِنْسِ
IndefiniteSingularFeminineGenitiveRootA SpringPatternضNounGeneric or common Noun
Surah/Below is the only verse in the holy Quran containing the indefinite, accusation nounعَيْنٍ
Verse 
88-5They will be given to drink from a boiling hot springتُسْقَى مِن عَيْنٍ ءَانِيَةٍ