BABU ‘N-NISA باب النسا
“The Women’s Gate.” In later years, as Muhammad added to the number of his wives, he provided for each a room or house on the same side of the mosque at al-Madinah. From these he had a private entrance into the mosque used only by himself, and the eastern gate still bears in its name, Babu ‘n-Nisa’, the memory of the arrangement. (Muir’s Life of Mahomet, iii. p.20.)
Based on Hughes, Dictionary of Islam