Idghaam (إدغام) means "merging" or "assimilation." It describes how a resting noon (نْ) or tanween merges into whatever letter follows it, so instead of two separate sounds, you get one stressed, doubled letter.
The Two Types
Idghaam With Ghunnah
Occurs with four letters, ya, noon, meem and waw, remembered together as "yanmoo." The merging carries a nasal ghunnah sound held for about two counts.
Idghaam Without Ghunnah
Occurs with two letters, lam and ra. Here the noon merges completely into the next letter with no nasal sound at all, a fully clean merge.
How It's Actually Pronounced
Rather than saying the noon and then the next letter separately, the two blend into one, with the following letter effectively doubled. Whether that merge carries a nasal hum or not depends entirely on which of the six letters is doing the merging.
An Important Exception
Idghaam only applies between two separate words, or where the noon is at the end of one word and the triggering letter starts the next. Within a single word, this particular merge doesn't apply the same way, a detail worth learning directly from a teacher since it's easy to misapply otherwise.
How to Learn Idghaam Properly
Start by memorising the six letters split into their two groups, that's genuinely most of the battle. Then practice example words for each type separately before mixing them in full verses. A teacher correcting your ghunnah timing live, the same two-count standard used across several noon sakinah rules, catches errors that are hard to hear in your own recitation.
Frequently Asked Questions
What does Idghaam mean in Tajweed?
Merging a resting noon or tanween into the following letter, so both are pronounced as one stressed sound.
What are the letters of Idghaam?
Six letters split into two groups: ya, noon, meem, waw (with ghunnah), and lam, ra (without ghunnah).
What's the difference between Idghaam with and without ghunnah?
With ghunnah adds a two-count nasal sound during the merge. Without ghunnah merges completely cleanly, with no nasal hum.
Does Idghaam happen within a single word?
Generally no, it applies between two separate words, or across a word boundary, which is an important exception worth learning directly.
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