Idghām of Nūn Sākinah and Tanwīn: The Tajweed Rule of Merging (UK British Muslim Guide)

Idghām means "merging" — when a stationary nūn (نْ) or a tanwīn (ـً ـٍ ـٌ) is followed by one of six specific letters, the nūn or tanwīn is merged into the following letter. This piece explains the rule, lists the six letters, distinguishes idghām with ghunnah from idghām without, and gives Qur'anic examples British Muslim students will recognise.

The four rules of nūn sākinah and tanwīn — quick recap

1. Iẓhār — clear pronunciation when followed by 6 throat letters (أ ه ع ح غ خ)
2. Idghām — merging when followed by 6 specific letters (ي ر م ل و ن) — this article
3. Iqlāb — conversion to mīm sound when followed by bāʾ (ب)
4. Ikhfāʾ — concealment when followed by the remaining 15 letters

The six letters of idghām: ي ر م ل و ن

Memorise the mnemonic word: Yarmaluwna (يرملون). Each letter of the mnemonic is one of the idghām letters.

• Yāʾ (ي)
• Rāʾ (ر)
• Mīm (م)
• Lām (ل)
• Wāw (و)
• Nūn (ن)

Two sub-types of idghām

Idghām with ghunnah (إدغام بغنة)

When the following letter is one of: ي م ن و (yāʾ, mīm, nūn, wāw — mnemonic: yanmū ينمو).

The nūn or tanwīn is merged into the following letter, and the merger is accompanied by a 2-count nasal ghunnah hold.

Idghām without ghunnah (إدغام بغير غنة)

When the following letter is one of: ل ر (lām, rāʾ).

The nūn or tanwīn is merged into the following letter with no nasal hold. The transition is clean and immediate.

Qur'anic examples

With ghunnah

• "Khayrun yawmaʾidhin" — tanwīn followed by yāʾ. Merge with 2-count ghunnah.
• "Min waliyyin" — nūn followed by wāw. Merge with ghunnah.
• "Maliki yawmi-d-dīn" — Surah al-Fātiḥah verse 4. Tanwīn followed by yāʾ-like sound (depending on linkage).
• "Mawʾūdatan nuʿallimuhā" — tanwīn followed by nūn.

Without ghunnah

• "Min rabbihim" — nūn followed by rāʾ. Merge cleanly, no ghunnah.
• "Min ladunhu" — nūn followed by lām. Merge cleanly.
• "Hudan li-l-muttaqīn" — Sūrah al-Baqarah 2:2. Tanwīn followed by lām.

The exceptions

Idghām only applies when the nūn sākinah and the following idghām letter are in different words. If they are in the same word, the rule is iẓhār muṭlaq (absolute clarity) — no merging.

The four classical examples within a single word:

• Dunyā (دنيا)
• Bunyān (بنيان)
• Qinwān (قنوان)
• Ṣinwān (صنوان)

In all four, the nūn is pronounced clearly even though wāw or yāʾ follows.

Common British Muslim student mistakes

1. Adding ghunnah to lām/rāʾ idghām. The nasal hold belongs only to ينمو, not to ل ر.
2. Skipping ghunnah on ينمو merger. The 2-count nasal hold is mandatory.
3. Over-pronouncing the merged nūn. The nūn vanishes into the following letter — it should not be audible as a separate sound.
4. Forgetting the in-word exceptions. Dunyā is a word every British Muslim child says often — get the iẓhār right.

Why this is the most-applied tajweed rule

Nūn sākinah and tanwīn occur thousands of times across the Qur'an. Idghām is one of the most frequent of the four nūn rules. A British Muslim who masters this rule has solved a substantial portion of their tajweed correction at one stroke.

The other nūn sākinah rules

• Iẓhār: clear pronunciation when followed by ء ه ع ح غ خ. Memorise in this guide as a follow-up.
• Iqlāb: when followed by bāʾ (ب), the nūn is converted to a mīm sound with ghunnah. Example: "min baʿd" sounds like "mim-baʿd".
• Ikhfāʾ Ḥaqīqī: concealment when followed by the remaining 15 letters. The nūn is partially hidden with 2-count ghunnah.

This article serves as the canonical Nūn Sākinah pillar — Iqlāb and Ikhfāʾ Ḥaqīqī are summarised here; Iẓhār was historically a separate post.

How to drill idghām as a British Muslim

1. Memorise the yarmaluwna mnemonic. Without it, you cannot identify the rule in the moment.
2. Sub-divide into yanmū vs. lām/rāʾ. The ghunnah question depends on this distinction.
3. Drill on Sūrah al-Fātiḥah: "hudan li-l-muttaqīn"-equivalent transitions occur frequently.
4. Listen to a master qārī: notice how the merged sound is one stressed letter, not two.
5. Get corrected: ghunnah length errors are easy to miss in self-practice.

Closing

Idghām of nūn sākinah is one of the four foundational tajweed rules for nūn. Master it and a substantial portion of your Qur'anic recitation snaps into place. Book a free Eaalim trial with an Al-Azhar trained teacher who can take you through all four nūn rules systematically.