Wikipedia
Kalfa (Turkish for "apprentice, assistant master") was a general term in the Ottoman Empire, for the women attendants and supervisors in service in the palace. Novice girls had to await promotion to the rank of Kalfa. It was a rank below that of Usta ("master"), the title of the leading administrative/supervisory officers of the harem. The titles usta and kalfa belong to the terminology of Ottoman guild organization and other hierarchically organized corporate bodies. Officially slaves or service girls, depending on their rank these women could wield considerable authority and influence in their duties and were generally treated with much respect by lower ranking attendants in the harem as well as by members of the imperial family.