Does Qiniangma refer to seven fairies or only the seventh?

I understand Qiniangma as seven fairies, not just the seventh in order. Ordinary forms of address offer a clue: for ranking we usually say something like elder seven or little seven, whereas Qiniangma sounds more like a reference to the seven fairies.

Folk belief regards Qiniangma as children's guardians and connects this with the Cowherd and Weaver Girl legend. After the Weaver Girl returns to heaven and meets the Cowherd only once yearly, the children cannot often be with their mother. The other fairies pity them and wish to protect and care for them, giving the tradition its child-guarding meaning. Understanding the name reveals the story's care for mothers and children. This explains a folk legend, not verified history or guaranteed outcomes for children.