The Sura (or Surah) is a name for a chapter of the Koran. The chapters are roughly ordered from longest to shortest. Each sura is divided into an ayat.
List of Suras
Al Fatiha, or "سورة الفاتحة ," is the sura that is traditionally placed first. It invokes the name of Allah as the one true God, and praises him as being merciful and the true path to salvation. It is considered the most important sura by many scholars of Islam, and is said repeatedly throughout the day during traditional Muslim prayer (salat).