Dar al-Islam: This term refers to the geographic area where Islam and its laws hold sway. It includes regions where Muslims are the majority or have significant political power.
Caliphate: A caliphate is an Islamic state led by a caliph who serves as both a political leader and a religious authority. It played a crucial role in promoting and expanding Islam during periods of Islamic expansion.
Jihad: Jihad means 'struggle' or 'striving' in Arabic. In the context of Islamic expansion, it can refer to both internal struggles for personal improvement or external efforts to defend or spread Islam.