This short story, which is the first in Joyce's collection of short stories entitled Dubliners, captures the complexity of life and explores the character of the dead priest, Father Flynn, who is examined through the testimony of three characters. This story, as with all of the short stories in this collection, is based around an epiphany, when the central character experiences a sudden revelation or moment of self-understanding which allows them to grow up or mature, passing some kind of ritual allowing them to move towards adulthood.
One reason that the title "The Sisters" was chosen is that it is the testimony of one of Father Flynn's sisters that allows the narrator to go through this rite of passage and achieve his epiphany. The reader is initially presented with the narrator's own remembrances of Father Flynn, which are nostalgic, then the suspicions of Old Cotter about Father Flynn, which put him in an altogether sinister light. Finally, it is Eliza's account of his final days that allows the reader to see the mental pressure he was under and how that became too much for him. Note what Eliza says about her deceased brother:
He was too scrupulous always, she said. The duties of the priesthood was too much for him. And then his life was, you might say, crossed.
It is at this point that the narrator is able to approach the table and taste the sherry, a clear copy of a first communion ceremony, that indicates how important this moment is as a rite of passage and signals the epiphany. The short story is therefore called "The Sisters" because it signals the importance of Eliza and Nannie, the sisters of Father Flynn, in revealing crucial information about Father Flynn and his character, which leads to the epiphany of the narrator.