Why is seven sisters named so?

The term "Seven Sisters" refers to a group of seven states in northeastern India: Arunachal Pradesh, Assam, Meghalaya, Manipur, Mizoram, Nagaland, and Tripura. The name is believed to have originated from the geographical and cultural similarities among these states, as well as their close proximity to each other. The states are often referred to collectively due to their shared heritage and challenges, as well as their picturesque landscapes. Additionally, the Seven Sisters are sometimes accompanied by the eighth state, Sikkim, which is often referred to as the "brother" of the group.