Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 6 months ago

Al Horoof al-Muqatta'a or al-Muqatta'aat are combinations of letters or single letter of the Arabic language in the beginning of 29 surahs in Qur'an. 27 of them are Makki surahs and only 2 are Madani - al-Baqara and Aal Imran.
Each letter is recited separately. Examples are Alif Laam Mim, Haa Mim and Alif Laam Ra.
No doubt there are meanings for every letter in Qur'an but the ulama have discussed these letters and have different opinions.
Some of the ulama say that it is a challenge to the Arabs - the fact that these letters are from their own language. It is a challenge to them to prove that they can never bring something like Qur'an.  When they failed, they were challenged to bring ten chapters like its chapters, and when failed, they were challenged to bring just one chapter like its chapters. They failed as well. That is very clear evidence that the Qur'an is not from a human source.
No doubt the meaning of these letters in Qur'an and the meaning of the whole Qur'an is fully with the Prophet Muhammad (SAWA) and with his Holy Projeny Ahlul Bayt (AS).
We have many narrations in this regard in the book of al-Shaykh al-Saduq known by Ma'ani al-Akhbar - the meanings of the narrations.
Many narrations about the meanings of some of the Al Horoof al-Muqatta'at like Alif Laam Ra is that it is the greatest name of Allah (SWT), Ta Haa is one of the names of the Prophet (SAWA).
In surah Maryam the first verse - Kaf Ha Ya 'Ain Sad - according a narration it refers to Karbala, the victimisation of Ahlul Bayt (as), the criminal Yazid, the thirst of Imam Hussain (as) and the patience of Imam Hussain (as).
These narrations are many but we can come to the conclusion that the detailed meanings of these letters are with the Prophet (pbuh) and Ahlul Bayt (as).
The ulama have also seen a link between these letters and the surah itself so if any surah starts with Alif Laam Mim, there is a link between these letters and the contents of the surah.
Many books were written on the subject of Al Horoof al-Muqatta'at:
·        Al Horoof al-Muqatta'at fil-Qur'an by Abd al-Jabbar Sharara
·        Awa'il al-Suwar fil-Qur'an al-Karim by Ali Nasuh Tahir
·        Al Horoof al-Muqatta'at fee awail al-Suwar al-Qur'aniya by Muhammad Ahmed Abu Firakh
·        Asrar al-Huruf, wa yalih al Horoof al-Muqatta'ah fil-Qur'an al-Karim by Kazim Muhammad Ali Shukr
·        Al Horoof al-Muqatta'at fee awail al-Suwar by Adil bin Ali bin Ahmed al-Shiddi
·        Al-Nadhr ila al-Ma'ani Al Horoof al-Muqatta'at by Hamid bin Abullah bin Ali
·        al-Muqatta'at fee Fawatih al-Suwar by Asmaa Tariq Ismail Rayyan
Briefly we say that the real meanings of these letters are best known by the Prophet (pbuh) and his Holy Projeny (as).