It is called Abbess
A gathering of nuns is called a nunnery. Or a convent.
Convent, Cloister, or Nunnery
Monastery is for priest and nunnery is for nuns
Reading Nunnery was created in 979.
Iona Nunnery was created in 1203.
Chupzang Nunnery was created in 1665.
Nenang Nunnery was created in 1333.
Negodong Nunnery was created in 15##.
Armathwaite Nunnery was created in 1092.
Ilchester Nunnery ended in 1463.
Ilchester Nunnery was created in 1220.
Cannington Nunnery was created in 1138.