Sometimes, I hear priests introduce themselves as "Brother Peter" or "Father Peter".
What's the difference between "Brother" and "Father" if they're both priests? Does it have something to do with the order they belong to? Or do they just prefer "Brother" instead of "Father" or vice versa?
Some sisters and nuns introduce themselves as "Sister Isabelle" or "Mother Isabelle".
What's the difference between "Sister" and "Mother"? Does this also have something to do with the order they belong to? Does "Mother" mean like Mother Superior?