In-laws

If you are married or have married family members, then you automatically acquired relatives by marriage, collectively known as in-laws.

For example, my sister's husband is my brother-in-law. Now, what if I had two married sisters? How would I refer to their husbands together, as my brother-in-laws or brothers-in-law? The answer is the second choice: brothers-in-law

Basically we are making a compound noun plural and to do this we add an s to the main word in the compound.

sisters-in-law
fathers-in-law
mothers-in-law

Is anyone married in your family? If so, who are your in-laws?