Final answer:
The term 'Dar al-Islam' refers to the spiritual and cultural unification under Islam that was facilitated through shared religious practices, a common legal system, and a network of trade and travel connecting various Islamic communities.
Step-by-step explanation:
The term Dar al-Islam refers to the spiritual and cultural unification under Islam. Despite the absence of a single political leader to unify the vast regions where Islam was practiced from the 7th century onwards, the Islamic world experienced a spiritual and cultural unification under the religion of Islam. This unification was facilitated through shared beliefs, religious practices, legal systems under sharia, and scholarly collaboration among the ulama. Moreover, trade and travel also played critical roles in spreading Islamic culture and practices, effectively creating a network that connected various kingdoms, empires, and communities within the Dar al-Islam, contributing to its economic and cultural cohesion.