Madd means prolongation i.e to stretch a sound for two counts. There are three madd letters which are alif, waaw and yaa.
These three letters are used to extend the three Arabic vowels:
1.Alif is used to extend fathah (a) and this madd is called «alif madd»
2.Yaa is used to extend kasrah (i) and this madd is called «yaa madd»
3.Waaw is used to extend dammah (u) and this madd is called «waaw madd»
The elongation itself is indicated on the letter as follows:
The colon in transcription denotes the elongation. In the examples above, you can see that the letters alif, yaa and waaw come after their vowel but these letters themselves do not have any vowels. The letters alif, yaa, waaw themselves are not being read too, e.g: بُو here we do not say «buw» we pronounce it as «bu:», so waaw is not being read. Thus, we understand that at this point we need to lengthen the vowel. There are examples of words with madd for each of the three vowels below:
In fact, the topic of prolongation (madd) is much broader and will be discussed in more detail in the fourth course of «Tajweed», in sha Allah. We have had only a brief look at it so far.