Divisions of the world in Islam

The Arabic singular form dar (دار), translated literally, may mean "house", "abode", "structure", "place", "land", or "country". In Islamic jurisprudence it often refers to a part of the world.

The idea of geographical divisions along religious lines i.e. the dur is not mentioned in the Quran.

The notions of "houses" or "divisions" of the world in Islam such as Dar al-Islam and Dar al-Harb does not appear in the Quran or the Hadith, the only authoritative sources of Islam. According to Abou El Fadl, the only dar the Qur'an speaks of is "the abode of the Hereafter and the above of the earthly life, with the former described as clearly superior to the latter". Early Islamic jurists devised these terms to denote legal rulings for ongoing Muslim conquests almost a century after Muhammad. The first use of the terms was in Iraq by Abu Hanifa and his disciples Abu Yusuf and Al-Shaybani. Among those in the Levant, Al-Awza'i was leading in this discipline and later Shafi'i.

Dar al-Islam (Arabic: دار الإسلام‎‎ literally house/abode of Islam; or Dar as-Salam, house/abode of Peace; or Dar al-Tawhid, house/abode of monotheism) is a term used by Muslim scholars to refer to those countries where Muslims can practice their religion as the ruling sect and where certain religions, (Judaism, Christianity, and Sabianism) are to be tolerated. It is the area of the world under the rule of Islam, literally, "the home of Islam." These are usually Islamic cultures wherein Muslims represent the majority of the population, and so the government promises them a privileged status. Most Dar al-Islam areas are surrounded by other Islamic societies to ensure public protection.

...
Wikipedia