Example of the spouse of one's sibling
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JonathanMary AnneDavid
David and Jonathan became brothers-in-law when David married Jonathan's sister Mary Anne

A sibling-in-law is the spouse of one's sibling, the sibling of one's spouse or the person who is married to the sibling of one's spouse.[1]

More commonly, a sibling-in-law is referred to as a brother-in-law for a male sibling-in-law and a sister-in-law for a female sibling-in-law.

Sibling-in-law also refers to the reciprocal relationship between a person's spouse and their sibling's spouse. In Indian English this can be referred to as a co-sibling (specifically a co-sister, for the wife of one's sibling-in-law,[2] or co-brother, for the husband of one's sibling-in-law[3]).

Relationships

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Siblings-in-law are related by a type of kinship called affinity like all in-law relationships. All of these are relations which do not relate to the person directly by blood.[1]

Just like the children of one's siblings, the children of one's siblings-in-law are called simply nieces and nephews – if necessary, specified whether "by marriage", as opposed to "by blood" or "by adoption".

If one pair of siblings is married to another pair of siblings, the siblings-in-law are thus doubly related, each of the four both through one's spouse and through one's sibling, while the children of the two couples are double cousins.

Culture

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One study, examining the issue of envy in the triadic system of sibling, sibling-in-law and spouse, concluded that "The sibling-in-law relationship shared similarities with both spousal and sibling relationships" and that "Relational closeness and satisfaction for all relationships in the triad were correlated."[4]

In Islamic law (Sharia)[5] and Jewish law (halakha),[6] sexual relations between siblings-in-law are prohibited as incestuous, unless the spouse is no longer married. Conversely, in Judaism there was the custom of yibbum, whereby a man had a non-obligatory duty to wed his deceased brother's childless widow, so she might have progeny by him.[7]

See also

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References

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  1. ^ a b Cambridge Dictionaries Online. "Family: non-blood relations".
  2. ^ "Co-Sister". Cambridge Dictionary. Cambridge Dictionary. Retrieved 18 April 2020.
  3. ^ "Co-Brother". Cambridge Dictionary. Cambridge Dictionary. Retrieved 18 April 2020.
  4. ^ Yoshimura, C.G (2010). "The experience and communication of envy among siblings, siblings-in-law, and spouses". Journal of Social and Personal Relationships.
  5. ^ Quran 4:23 : "˹Also˺ forbidden to you for marriage...two sisters together at the same time"
  6. ^ Leviticus 18:16, 18:18.
  7. ^ Deuteronomy 25:5–10.