- The spellings sister-kin and sisterkin are both used in the books.
The term "sisterkin" seems to be used in three main ways, with rather different meanings, as seen here:
- to refer to all the Highborn women who are initiated into the rings of secrecy, the "community of sister-kinship"
- By then, of course, many of them would belong to the community of sister-kinship which would be their only true "home" as adults.
- very close relationships between pairs of women
- "Adiraina and I were sisterkin."
- the relationship between a woman and her partner's family
- "[Tieri] was sister-kin to me, the daughter of Telarien, the granddaughter of my dear, dead Kinzi."
The second usage is by far the most common.
A girl's mother's name appears to be necessary to initiate her into sister-kinship; presumably the general form is meant here. There is no explanation as to why, but the Matriarchs use this as a reason to demand the name of Jame's mother.
A sister-kin relationship appears to be arranged by the Matriarchs rather than occurring spontaneously; Adiraina speaks of "hoping for a glimpse of her new sister-friend.". Before the final vows of sister-kinship, such couples appear to call each other "sister-friend" rather than "sister-kin".
While due to its intensely secretive nature, it can be hard to pin down sister-kinship as one exact definition, they are by and large lovers. Adiraina refers to Kinzi, her sister-kin, as "her lover". Sister-kin may sleep in the same bed when they are in Gothregor;.
It's also worth acknowledging that all sister-kinships are not necessarily identical. It is completely possible that the nature of sister-kinships vary as their members do.
The duties of Highborn women mean that the sister-kin relationship is generally a long-distance one, continued through coded messages in the knot-stitch code in the token scarves they regularly exchange to the bemusement of Highborn men.
- Brenwyr and Aerulan
- Adiraina and Kinzi
- Jamethiel Dream-Weaver and a Knorth Shanir girl, who clawed out her eyes during the Falling, having seen what Jamethiel had done.
- A Coman instructress from Seeker's Mask, and an Edirr girl