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الأسماء الخمسة — The Five Special Nouns

The five special nouns are a group of nouns that decline using letters (long vowels) instead of short vowel marks, when they are the first term of an iḍāfa (muḍāf).


The Five Nouns

Noun Meaning
أَبٌ father
أَخٌ brother
حَمٌ father-in-law (husband's relative)
فُوهٌ (with meem dropped: فَم) mouth
ذُو possessor of / owner of

Declension When in Iḍāfa

Case Sign Form Example
مرفوع (nominative) وَاو أَبُو / أَخُو / فُو / ذُو أَبُو بَكرٍ جَاءَ
منصوب (accusative) أَلِف أَبَا / أَخَا / فَا / ذَا رَأَيتُ أَبَا بَكرٍ
مجرور (genitive) يَاء أَبِي / أَخِي / فِي / ذِي مَرَرتُ بِـأَبِي بَكرٍ

When not in iḍāfa: they take regular short vowel endings like any other noun (أَبٌ، أَبًا، أَبٍ).


The Special Case of فَم (Mouth)

فَم has two forms:

  1. With meem retained: فَمٌ → declines normally with short vowels: فَمٌ، فَمًا، فَمٍ
  2. With meem dropped: فُوهٌ → becomes فُو (nominative), فَا (accusative), فِي (genitive) when in iḍāfa

The five-noun declension only applies when the meem is dropped.


Why This Matters in the Hadith Text

رَضِيَ اللهُ عَنهُمَا — when referring to ابن عبَّاس, the dual is used because the chain of narration mentions both Abdullah ibn Abbas and his father Abbas — two sahabis. The noun أَب (as in عَن أَبِيهِ) appears in the genitive, correctly showing يَاء as the genitive marker.

Quick reference

Case Marker Mnemonic
رفع وَاو أَبُو عَبداللهِ
نصب أَلِف رَأَيتُ أَبَا عَبداللهِ
جرّ يَاء مَرَرتُ بِأَبِي عَبداللهِ

Session References

  • From Esfahaan to Madinah Session 1: five special nouns introduced; فَم and its two forms; dual example with ابن عباس