The additive form is a special phrase in which we add one noun to another one. Examples are like saying:

• Ahmed's house
• The kid's toy
• The father's car

It is also sometimes referred to as the possessive form because it means that one object belongs to another one. For example, when we say

• Ahmed's house

we mean that the house belongs to Ahmed. It is like saying

• The house of Ahmed

In Arabic, the additive form is called Idafah: إِضَافَة

Examples for the Additive Form

Read each of the sentences below and it's translation. Notice how the additive form in Arabic has the two nouns switched, and there is no notion of an apostrophe 's

•  This is Ahmed’s house.

هَذِا بَيْتُ أَحْمَد.

• This is the child's ball.

هَذِه كُرَةُ الطِّفْلِ.

• This is the teacher's (masculine) book.

هَذَا كِتَابُ المُعَلِّمِ.

• This is the teacher's (feminine) book.

هَذا كِتاب المُعَلِّمَةِ.

• This is my brother's daughter.

هَذِه بِنْتُ أَخِى.

• This is my friend's (feminine) sister.

هَذِه أُخْتُ صَدِيقَتِى.

• This is my friend's (masculine) sister.

هَذِه أُخْتُ صَدِيقِى.