عباسی refers to the Abbasid Caliphate, which was a major Islamic dynasty that ruled from 750 to 1258 CE. It emerged after the overthrow of the Umayyad Caliphate and is known for its cultural, scientific, and economic achievements. The capital was established in بغداد, which became a center of learning and trade during this period. The Abbasids promoted the arts and sciences, leading to advancements in various fields such as mathematics, astronomy, and medicine. This era is often associated with the Golden Age of Islam, where scholars like ابن سینا and الخوارزمی made significant contributions that influenced both the Islamic world and Europe.