A surah (; , , ) is the equivalent of "chapter" in the Qur'an.
There are 114 surahs in the Quran, each divided into ayats (verses). The chapters or surahs are of unequal length; the shortest surah (Al-Kawthar) has only three verses while the longest (Al-Baqara) contains 286 verses. The Quran consists of one short Chapter (Q1); eight very long chapters, making up one-third of the Qurʾān (Q2‒9); 19 mid-length chapters, making up another one-third (Q 10‒ 28); and 86 short and very short ones of the last one-third (Q 29‒114).
Of the 114 chapters in the Quran, 86 are classified as Meccan, as they were revealed before the Hijrah, while 28 are Medinan, as they were revealed after. This classification is only approximate in regard to the location of revelation; any chapter revealed after migration of Muhammad to Medina (Hijrah) is termed Medinan and any revealed before that event is termed Meccan. However, some Meccan surahs contain Medinian verses (verses revealed after the Hijrah) and vice versa. Whether a surah is Medinian or Meccan depends on if the beginning of the surah was revealed before or after the Hijrah.
The Meccan chapters generally deal with faith and scenes of the Hereafter while the Medinan chapters are more concerned with organizing the social life of the nascent Muslim community and leading Muslims to the goal of darul islam by showing strength towards the unbelievers. Except for surah At-Tawbah, all chapters or surahs commence with "In the Name of Allah, Ar-Rahman (The Beneficent), Ar-Rahim (The Merciful)". This formula is known as the Basmala and denotes the boundaries between chapters. The chapters are arranged roughly in order of descending size; therefore the arrangement of the Quran is neither chronological nor thematic. Surahs (chapters) are recited during the standing portions (Qiyam) of Muslim prayers. Surah Al-Fatiha, the first chapter of the Quran, is recited in every unit of prayer and some units of prayer also involve recitation of all or part of any other surah.
Etymology
The word surah was used at the time of Muhammad as a term with the meaning of a portion or a set of verses of the Quran. This is evidenced by the appearance of the word surah in multiple locations in the Quran such as verse 24:1: "A surah that We have sent down and appointed, and We have sent down in it signs, clear signs, that haply you will remember." (see also verses 2:23, 9:64, 86, 124, 127, 10:38, and 47:20). It is also mentioned in plural form in the Quran: "Or do they say, He invented it? Say, "Then bring ten surahs like it and call upon whomever you can besides God, if you are truthful."
In 1938, Arthur Jeffery suggested that the name derived from the Syriac word surṭā meaning 'writing'.
Chronological order of chapters
Chapters in the Quran are not arranged in the chronological order of revelation, and the precise order has eluded scholars. According to hadith, Muhammad told his companions the traditional placement of every Wahy as was revealed to him, and Wm Theodore de Bary, an East Asian studies expert, describes that "The final process of collection and codification of the Quran text was guided by one over-arching principle: God's words must not in any way be distorted or sullied by human intervention. For this reason, no attempt was made to edit the numerous revelations, organize them into thematic units, or present them in chronological order...".
Early attempts
A number of medieval Islamic writers attempted to compile a chronologically ordered list of the chapters, with differing results. As no transmitted reports dating back to the time of Muhammad or his companions exists, their works necessarily represent the opinions of scholars, and none originates before the first quarter of the 8th century. One version is given in a 15th-century work by Abd al-Kafi, and is included in the chronological order given by the standard Egyptian edition of the Quran (1924). Another list is mentioned by Abu Salih, while a significantly different version of Abu Salih's is preserved in the book 'Kitab Mabani'. Yet another, from the 10th century, is given by Ibn Nadim.