Understanding the Arabic Idafa: The Possessive Construction (الْإِضَافَةُ)

The Idafa Structure (اَلْإِضَافَةُ)

The "Possessive Sandwich" of Arabic

In English, we show possession using "'s" (The student's pen) or "of" (The key of the car). In Arabic, we simply place two nouns side-by-side. This relationship is called Idafa.

1. Mudāf (مُضَاف)

The "Possessed" item (the thing being owned).
Rule: It can never have "Al-" and never has Tanween (double vowel).

2. Mudāf Ilayh (مُضَاف إِلَيْهِ)

The "Possessor" (the owner).
Rule: It is usually Definite and its ending usually changes to Kasra (ـِ / ـٍ).

Common Examples

Arabic Phrase	Transliteration	Meaning
كِتَابُ الطَّالِبِ	Kitābu at-tālibi	The student's book
مِفْتَاحُ السَّيَّارَةِ	Miftāhu as-sayyārati	The car key
بَيْتُ عُمَرَ	Baytu Umara	Umar's house

⚠️ The Golden Rule

The first word (Mudaf) never takes the definite article "Al-". Its definiteness comes from the second word.
Incorrect: اَلْكِتَابُ الطَّالِبِ
Correct: كِتَابُ الطَّالِبِ

Practice: If Qalam (قَلَم) is "Pen" and Al-Mudarris (اَلْمُدَرِّس) is "The Teacher," how do you say "The teacher's pen"?
Answer: قَلَمُ الْمُدَرِّسِ (Qalamu al-mudarrisi).