فِي جِيْدِهَا

فِي جِيْدِهَا is a phrase (شِبْهُ الجُمْلَةِ) consisting of a particle and a possessive noun compound

PhraseParticle/Noun/NounNounNounParticle
شِبْهُ الجُمْلَةِ جَارٌ وَمَجْرُوْرٌ وَهُوَ مُضَافٌ وَ مُضَافٌ إِلَيْهِمُضَافٌ إِلَيْهِاسْمٌ مَجْرُوْرٌ وَهُوَ مَضَافٌحَرْفُ جَرٍّ
PhraseCompoundpossessive nounGenitive noun + Noun possessedParticle of pulling down
  
 فِي جِيْدِهَا=هَا+جِيْدِ+فِي
 in her neckhersneck ofin
Surah/Below is the only verse in the holy Quran containing the compoundفِي جِيْدِهَا
Aayat
111-5In her neck a rope of palm fiberفِي جِيْدِهَا حَبْلٌ مِّنْ مَّسَدٍ