The ethnonym Afghan ( ) has been used in the past to refer to members of Pashtun tribes, and that usage persists in some places in Afghanistan. The name Afghanistan ( ; Afghan + -stan) is a derivation from the ethnonym Afghan, originally in the loose meaning "land of the Pashtuns" and referred to the Pashtun tribal areas south of the Hindu Kush. Initially they were known as "Abgan" during 1st and 2nd century, later in 3rd century, the Sassanids mention a eastern tribe called Abgân, which is attested in its Arabic form (Afġān) in the 10th century Ḥudūd al-ʿĀlam. Through the nineteenth century, the term "Afghan" was used by various writers as a synonym for "Pashtun", but such usage now is rare in English.