For example, is my sister’s sister in law my sister in law? I’m talking about my sister’s husband’s brother’s wife.

No, she’s fair game – go for it !

Out-laws

Is this Sandra? Dave’s daughter? You know, the one who did that thing to that horse on a Tuesday?

Nah, you’re thing of Jeanette, and it was a zebra

sister in law once removed???

😆 @scaredy

is my sister’s sister in law my sister in law?

No, it’s pretty complicated, but… hang one just working it out.. yep. According to my family relationship calculator (can’t believe you haven’t got one), she is, in fact…
Your sister’s sister-in-law.

Yep that’s it.

Sister in law once removed???

I think once removed refers to generations. She’s just your sister’s sister in law.

What about my brother in-law’s brothers? Are they my brothers-in-law?

your brothers brother in laws are the brothers of the sister your brother married, they are usually not fair game unless you are your brothers sister….