Idgham is joining a non-vowel with a vowel so that the two letters become one letter of the second type. Idgham With Ghunna is the first type of Idgham, which is called Idgham with nasalization (Ghunnah). Ghunnah is a sound that comes out of our noses.
Rule Color:
بِسۡمِ ٱللَّهِ
Rule Letters:
(ي، ن، م، و) < (نْ or ـًـٍـٌ)