A sura (pl. suwar) is a division of the Qur'an
The Quran , also transliterated Qur'an, Koran, Alcoran, Qur’ān, Coran, Kuran, and al-Qur’ān, is the central religious text of Islam, which Muslims consider the verbatim word of God . It is regarded widely as the finest piece of literature in the Arabic language...

, often referred to as a chapter. The term chapter is sometimes avoided, as the suras are of unequal length; the shortest sura (Al-Kawthar) has only three ayat
Ayah or Aayah is the Arabic word for sign or proof:"These are the Ayat of Allah, which We recite to you with truth...

 (verses) while the longest (Al-Baqara
Sura al-Baqarah is the second and longest chapter of the Qur'an. It is a Medinan sura and comprises 286 verses, including the single longest verse in the Qur'an...

) contains 286 ayat. Of the 114 suras in the Qur'an, 86 are classified as Meccan
Meccan sura
The Meccan suras are the chronologically earlier suras of the Qur'an that were, according to Islamic tradition, revealed anytime before the Hijrah . The other type of sura is the Madinan sura....

 while 28 are Medinan - this classification is only approximate as regards location of revelation - in actual fact, any sura revealed post-Hijrah
Hijra (Islam)
The Hijra is the migration or journey of the Islamic prophet Muhammad and his followers from Mecca to Medina in 622 CE. Alternate spellings of this Arabic word are Hijrah, Hijrat or Hegira, the latter following the spelling rules of Latin.- Hijra of Muhammad :In September 622, warned of a plot to...

 is termed Medinan and any revealed before that event is termed as Meccan.