what is idhgam billaghunah and idhgam malaghunah

Question
What is idhgam billaghunah and idhgam malaghunah

Answer
Idgham without a ghunnah and idghaam with a ghunnah.  Idgham means merging- when two letters are next to each other on the first letter merges into the second letter.   With the saakinah and tanween there are two types of merging into the the next letter, which must be one of the letters in the letters which form the word: .  The first type of idghaam is when there is a ghunnah, , and the second time is idghaam without a ghunnah,
Please see the following link for details and more explanation:
http://www.abouttajweed.com/the-noon-saakinah-and-tanween/merging-of-the-noon-saakinah-and-tanween-p-2.html