وَهُوَ نُونُ التَّثْنِيَةِ وَالْجَمْعِ، نَحْوُ: «جَاءَنِي غُلَامُ زَيْدٍ وَغُلَامَا زَيْدٍ وَمُسْلِمُو مِصْر».
Translation: The nūn of the dual and sound plural also stands in for tanwīn; the book illustrates “Zayd’s servant,” “Zayd’s two servants,” and “the Muslims of Egypt.”
غُلَامَانِ becomes غُلَامَا زَيْدٍ in iḍāfah.
The dual nūn drops, but the nominative alif remains.