the fear of nuns is called "monachousaphobia"
A gathering of nuns is called a nunnery. Or a convent.
Homer left the nuns for a while because he felt restless and a vague unhappiness clouding his thoughts.
Nuns
Girls who were training to be nuns would be postulants when they start, and then novices. The Catholic Orders do not allow boys to be nuns or sisters.
Nurses are NOT typically called "sister or sisters", and would likely be seen as a put down in the US. However, many Nuns train to be nurses. Because they are Nuns, they are called Sisters.
Mary founded an order of nuns called the Sisters of St Joseph of the Sacred Heart.
Sisters of Charity
prior
Yes; they are called "Brides of Christ".
Nuns cannot marry at all whilst they are nuns. They can leave the convent with the permission of the Mother Superior, and therefore marry one man, but a nun would never dream of marrying more than one man. This is bigamy if she is married to two men at a time, and nuns do not believe in divorce.
Nuns are solemnly professed religious sisters who live in a monastery, usually called an Abbey. Please note that Nuns are NOT Sisters. Sisters in the Catholic Church are religious women who take perpetual or simple promises, and usually live in a convent, teaching or nursing.