Explanation

Hazrat Ummay Salma (RA) is the wife known by the title Umm-ul-Masakeen. Hazrat Ummay Habiba (RA) was another respected companion but not primarily known by this specific title. Hazrat Zainab bint e Khuzaiymah (RA) is a different individual and does not hold this title. Hazrat Zainab Bint-t-Jahsh is also a different person.