I'rab · i'rabI'rab marker (alama)advanced term76+ in the Quran
Also written: Tanween · Nunation · Double vowel endings
In one line
Tanwin — the doubled end-vowel (-un / -an / -in): a spoken nun that is never written as a letter.
Classical definition
التَّنْوِينُ نُونٌ سَاكِنَةٌ تَلْحَقُ آخِرَ الاسْمِ لَفْظًا وَوَصْلًا، وَتُفَارِقُهُ خَطًّا وَوَقْفًا.
“Tanwin is an unvowelled nun attached to the end of a noun in speech and joined reading, which leaves it in writing and in pause.”
(بتصرف من شذا العرف)
Key words in the Arabic
نُون سَاكِنَةan unvowelled n-sound
لَفْظًا وَوَصْلًاin speech, when reading on
خَطًّا وَوَقْفًاin writing and when pausing
Understand it
Say كِتَابٌ aloud — kitābun — and you hear an n the script never writes as a letter: that is tanwin, marked by doubling the final vowel-sign. It usually accompanies indefiniteness, but not always: proper names like مُحَمَّدٌ carry it while fully definite. Its dependable rules are mechanical — it vanishes when ال arrives or when the noun leads an idafa, and diptotes refuse it altogether.
How to spot it
Recognition test
A doubled final vowel-sign — pronounce it and you hear the hidden n. The three forms map straight onto the cases: ـٌ = raf', ـً = nasb, ـٍ = jarr. In an indefinite noun the tanwin is where the case lives: جَاءَ رَجُلٌ، رَأَيْتُ رَجُلًا، مِنْ رَجُلٍ.
In the Quran
وَلَقَدْ نَصَرَكُمُ اللَّهُ بِبَدْرٍ وَأَنتُمْ أَذِلَّةٌ
Al 'Imran 3:123 — “And Allah had certainly helped you at Badr when you were weak”
بَدْرٍ carries jarr tanwin after بِ, and أَذِلَّةٌ carries raf' tanwin as the khabar. Two tanwins, two cases, both doing exactly what the rule predicts.
Related terms
▶ Watch the lessons
From the free course The Language of Quran — Easier than English (Book 1) (LoQ1), taught by Ustadh Muhammad Arjan Ali.
Common questions
How is tanwin pronounced if the noon is never written?
The doubled vowel mark itself carries the n: كِتَابٌ = kitābun, كِتَابًا = kitāban, كِتَابٍ = kitābin. In pause (waqf) the tanwin drops — nasb tanwin becomes a long ā, which is why ـً is usually written on an added alif.
Domain: I'rab · Category: I'rab marker (alama) · Frequency in the Quran: 76 · Source: بتصرف من شذا العرف, cross-checked against the Quranic corpus · Reviewed by Ustadh M. Arjan Ali