A Sūrah (سورة, or sura) is a chapter of the Qur'an. Of all the 114 surahs, 86 were revealed at Mecca (the earlier Meccan surahs), and the remaining 28 were revealed at Medina after Muhammad's hijra from Mecca (the later Medinan surahs).
Similarly, āyah (آية, plural آيات āyāt) is the Arabic word usually used to refer to one of the 6236 verses (6348 including all the Bismillahs) of the Qur'an.
 See Also
- Understanding the Qur'an - A hub page that leads to other articles related to Understanding the Qur'an
- Zarkashi, B.: Al-burhan fi 'ulum al-Qur’an, Cairo, 1958,Vol. 1, pp. 193-194
- Allamah Abu 'Abd Allah al-Zanjani - The History of the Quran - Al-Tawheed Vol. 4, No. 3; Vol. 5, No. 1, 2, & 3