The terms "nun" and "sister" are often used
interchangeably. However within Roman
Catholicism, there is a difference between the
two. Here's a simple summary of the differences.
A Catholic nun is a woman who lives as a
contemplative life in a monastery which is usually
cloistered (or enclosed) or semi-cloistered. Her
ministry and prayer life is centered within and
around the monastery for the good of the world.
She professes the perpetual solemn vows living a
life according to the evangelical counsels of
poverty, celibacy, and obedience. Check out the
Carmelite Nuns of Baltimore for example.
A Catholic sister is a woman who does lives,
ministers, and prays within the world. A sister's
life is often called "active" or "apostolic" because
she is engaged in the works of mercy and other
ministries that take the Gospel to others where
they are. She professes perpetual simple vows
living a life according to the evangelical counsels
of poverty, celibacy, and obedience. Check out the
IHM Sisters of Monroe, Michigan for example.
Because both nuns and sisters belong to the
church life form of Religious Life, they can also be
called "women religious."
As you might have noticed, there is a difference in
the type of vows, solemn vs. simple. The New
Commentary on the Code of Canon Law
explains the distinction this way:
