Some questions that might or might not be all that quick

[eldin raigmore]

The legalization of same-sex marriages raises some questions.
I do not need to know the answers because of anyone I know or have met IRL or even heard of IRL.
(I know Pete Buttigieg and Anderson Cooper have husbands; but I don’t know if either of them, nor either of their husbands, have any siblings!)
…
What do we call the relationship between a person and their father’s husband?
Stepfather, maybe?
…
What do we call the relationship between a person and their brother’s husband?
Brother-in-law, maybe?
…
What do we call the relationship between a person and their son’s husband?
Son-in-law, maybe?
…
Similarly:
Is a person’s mother’s wife their stepmother?
Is a person’s sister’s wife their sister-in-law?
Is a person’s daughter’s wife their daughter-in-law?
….
….
The rising popularity of polyamory generates a couple of questions, too!
It may be premature to ask them already, because as far as I know no jurisdiction in the UK or USA or Canada or Australia recognizes such unions as marriages; but I’ll ask them anyway!
…
What do we call the relationship between a person and their husband’s wife?
What do we call the relationship between a person and their wife’s husband?
….
….
In case polyamory and same-sex marriage overlap, there are two remaining questions of this type:
What’s the relationship between a person and their husband’s husband?
What’s the relationship between a person and their wife’s wife?

[Salmoneus]

What do we call the relationship between a person and their son’s husband?
Son-in-law, maybe?

How is this, or any of these, a 'maybe'? That's literally the definition of the word; the male spouse of your child is your son-in-law. I find it hard to believe you don't already know that. Etc.

[assuming for the parent questions that they weren't married when they had you, otherwise obviously they're your father or mother]

Are these serious questions, or just trolling?

What do we call the relationship between a person and their husband’s wife?
What do we call the relationship between a person and their wife’s husband?

"We" don't have clear terms for these relationships, due to their rarity, illegality, and taboo nature. "Sister-wife" was used extensively in discussing other cultures; "co-wife" and "co-husband" are also used. Individual polygamists and individual polygamous subcultures and communities may have their own terms.

[Creyeditor]

"We" don't have clear terms for these relationships, due to their rarity, illegality, and taboo nature. "Sister-wife" was used extensively in discussing other cultures; "co-wife" and "co-husband" are also used. Individual polygamists and individual polygamous subcultures and communities may have their own terms.

Papua Indonesian has terms for your grandfather's "other" wifes, depending on their relative age (or date of marriage). Nenek muda (lit. young grandmother) is a younger wife and nenek tua (lit. old grandmother) is an older wife, IIRC. I don't know about terms for co-wifes or your father's wife, maybe it's a generational thing.

[Khemehekis]

What do we call the relationship between a person and their husband’s wife?
What do we call the relationship between a person and their wife’s husband?

The English words for these are "co-wife" and "co-husband". I have "co-husband" and "co-wife" in my English-Kankonian dictionary. Kankonian, spoken in a country with both same-sex marriage and polygamy, uses muyeashelti ("also-spouse" or "fellow-spouse") for both.

[Khemehekis]

ObConlang: For those who are wondering, the kinship terms from Kankonian:

Spoiler:

mother: helemas
father: hoimas
parents: homoses
sister: zwaniz (pl. zwanzu)
brother: zhered (pl. zherdu)
sibling: surten (pl. surtei)
twin sister: bamzwaniz (pl. bamzwanzu)
twin brother: bamzhered (pl. bamzherdu)
wife/husband: ashelti
daughter: shara
son: yed
child: noto
aunt/uncle (parent's sibling): ladan
aunt/uncle (parent's sibling's spouse): mesim
niece/nephew (sibling's child): elfom
niece/nephew (spouse's sibling's child): herang
female cousin: mera
male cousin: kanwir
cousin: shaniz
female cousin on one's mother's side: mimera
male cousin on one's mother's side: mikanwir
cousin on one's mother's side: mishaniz
female cousin on one's father's side: hamera
male cousin on one's father's side: hakanwir
cousin on one's father's side: hashaniz
grandmother: emihelemas
grandfather: emihoimas
grandparents: emihomoses
granddaughter: obishara
grandson: obiyed
grandchild: obinoto
great-grandmother: emiemihelemas
great-grandfather: emiemihoimas
great-grandparents: emiemihomoses
great-granddaughter: obiobishara
great-grandson: obiobiyed
great-grandchildren: obiobinoto
great-aunt/great-uncle: emiladan
cousin once removed: shyudan
cousin twice removed: bamshyudan
cousin thrice removed: emshyudan
sister-in-law (spouse's sister): dzhemal
brother-in-law (spouse's brother): seres
sibling-in-law (spouse's sibling): dzhemes
sister-in-law (sibling's wife): pola
brother-in-law (sibling's husband): tomus
sibling-in-law (sibling's spouse): polus
sister-in-law (spouse's sibling's wife): eyeni
brother-in-law (spouse's sibling's husband): dondar
sibling-in-law (spouse's sibling's spouse): eyendar
mother-in-law: shefri
father-in-law: tarmat
parent-in-law: shefmat
daughter-in-law: selmi
son-in-law: dzheisi
child-in-law: selsi
in-laws: sheltshtanzes
stepmother: hevuhelemas
stepfather: hevuhoimas
stepparents: hevuhomoses
stepdaughter: hevushara
stepson: hevuyed
stepchild: hevunoto
stepsister: hevuzwaniz (pl. hevuzwanzu)
stepbrother: hevuzhered (pl. hevuzherdu)
stepsibling: hevusurten (pl. hevusurtei)
half-sister: bamiksizwaniz (pl. bamiksizwanzu)
half-brother: bamiksizhered (pl. bamiksizherdu)
half-sibling: bamiksisurten (pl. bamiksisurtei)
significant other, life partner: mabekad
co-wife/co-husband: muyeashelti (muyea for short)
sperm donor: kherisezhobor (kheso for short)
fiancée/fiancé: lai
surrogate mother: aghemas
surrogate father: aghoimas
surrogate parent: aghomoset (excerptal number)
sister from the womb: zwaniz ab fubos (zaf for short)
brother from the womb: zhered ab fubos (zhaf for short)
sibling from the womb: surten (pl. surtei) ab fubos (saf for short) (To see what these last three mean, read here)
widow/widower: okermi
semiwidow/semiwidower (polygamous person who has lost one/some spouse(s) but not all): minuokermi
angel mom: rentza
angel dad: tazga
broken-nester: emori