Why are some British nurses called "Sister"?

OK, I’ve done some research, and I know that there is a sort of hierarchy of nurses in Britain, and that not every nurse is called “Sister,” though it sure seems like it if you read enough British novels. What I can’t figure out is why the title “Sister” is used at all in referring to ANY British nurses. Since someone in the occupation is a nurse, it makes more sense to me to call that person “Nurse” than it does “Sister.”

There must be a logical explanation for this, Watson. I’d love to know what it is.

Perhaps from Church-affiliated hospitals?

Incidentally, ‘nurse’ in German is Krankenschwester – ‘sick sister’.

ETA: Nursing in the United Kingdom:

Nursing used to be the province of religious orders, especially orders of nuns. Hence the term Sister.

With the advent of male nurses and non-sexist language, Sister is moribund if not dead. “Matron” (now called Director of Nursing or similar) has also gone the way of the Dodo. These terms are only used by older people now. But I remember it from when I was a kid.

“Sister” (I’m told by Mrs Prosequi, who is one) meant that a nurse was a registered nurse, that is, one who could administer drugs, etc. There were other levels of assistant nurses who could not, and who did the crappy jobs like empty bedpans, bathe patients, etc. They used to have different uniforms, too. “Sister” was once a term of considerable authority. Particularly in rural areas, a long-serving Sister sometimes had more medical authority among the punters than some blow-in young smart-aleck doctor.

Enrolled Nurse, and Nurse Aide, if my Mum’s Nursing history is anything to go by.

And nurse in Hebrew is either *Achot *or *Ach *- “sister” or “brother”.

Yes, as said above, nursing was once the the province exclusively of nuns. In fact the first nurses’ uniforms were derived from the nun’s habit. You could still vaguely see the echos of the original in British nurses’ umiforms of the 50s, that weird white cap being all that’s left of the wimple, for instance.

Australian nurses, including the men, were called “sister” at least through the nineties. Don’t know about now. (I dated a nurse “sister” for quite a while.)

In Paul Scott’s Raj Quartet, set in British India, the white nurses are called “sister” and the mixed-race and Indian nurses are called “nurse.”

We use Sister and Brother in Arabic too.

Matrons were reintroduced in 2001. There are over 5000 of them today