Dickinson opens with a small puzzle. She has two sisters, one "in our house" and one "a hedge away," yet "there's only one recorded." The line sounds like a clerk checking a family register, and then the next one overturns it: "both belong to me." The poem is about the gap between the family you are given and the family you claim. The final name, "Sue," points to Susan, who married Dickinson's brother Austin and lived in the neighbouring house. That makes the hedge a real one, and it also serves as a neat image of closeness with a boundary still running through it.
The two sisters are drawn very differently. The first "came the road that I came" and "wore my last year's gown," which suggests shared childhood and hand-me-downs. Since Dickinson did have a sister, Lavinia, at home, this is probably her, though the poem never says so. The second sister arrives by another route. She is like a bird who "builded" her nest "our hearts among." The old-fashioned verb gives the line a slow, deliberate weight, as if the nest took real labour. This sister was not born into the family. She made a place in it.
The music imagery sharpens the difference. "She did not sing as we did – / It was a different tune," and she is "a music" to herself, "as Bumble bee of June." The comparison is affectionate and a little teasing. A bumblebee is self-sufficient, humming for its own reasons and busy in its own summer. Dickinson admires someone who does not need to match the family's tune.
The fourth stanza turns on a paradox: "I held her hand the tighter – / Which shortened all the miles." Hills usually lengthen a journey, but affection here shrinks the distance. The line also carries a quiet shift in time, since "Today is far from Childhood," and the poem begins to look back.
The fifth stanza is where the mood darkens and the writing gets stranger. The sister's "hum" still "deceives the Butterfly," as though it were so lifelike that a insect would be fooled by it. In her eye "The Violets lie / Mouldered this many May." Violets suggest spring and perhaps eye colour, but "mouldered" brings in decay. Judging by the imagery, memory has kept something alive and let it rot at once. Notice too that "May" echoes the sound of "away" from the first stanza, so the poem bends back toward its start.
The form supports this. Most of the poem moves in short, hymn-like lines, with a rhythm close to the church-hymn pattern of alternating longer and shorter lines. The opening, "One Sister have I in our house," is a steady eight syllables followed by a shorter, six-syllable line, and the effect is plain, almost conversational. The rhymes are mostly partial. "Tune" and "June" match fully, but "hills" and "miles," or "gown" and "among," only lean toward each other. The stanzas then shrink and loosen, with the fifth running to six lines and the last to five. Dickinson's dashes break the lines into hesitations and sudden turns, as if she is stopping to decide what to say next.
The ending is a declaration. "I spilt the dew – / But took the morn" sets a small loss against a larger gain. "I chose this single star / From out the wide night's numbers" plays the sky's countless stars against the one that matters. The key word is "chose." The first stanza spoke of what is "recorded," what simply exists on paper. Now the speaker has made a decision, and the last line, "Sue – forevermore!", is the only place where the poem names anyone and the only place it uses an exclamation mark. After so much suggestion and indirection, the bluntness lands hard.
The poem matters because it takes a familiar word, sister, and shows that it can mean two things. One kind of sisterhood comes with the family record. The other is something a person picks out of "the wide night's numbers" and keeps. Dickinson's poem does not rank them, since "both belong to me," but she saves her exclamation for the one she chose.