وَاعْلَمْ أَنَّ الْإِضَافَةَ عَلَى قِسْمَيْنِ: مَعْنَوِيَّةٍ وَلَفْظِيَّةٍ.
Translation: Know that iḍāfah has two kinds: semantic and formal (verbal).
Semantic iḍāfah yields definiteness or greater specification through the relationship.
Formal iḍāfah occurs when a descriptive word is added to its own dependent; its primary benefit is economy of expression.
We identify the kind from the syntactic relation, not merely from the appearance of two adjacent nouns.