Kinlaw

The parents of one's child-in-law.
Also, the two sets of parents of a married couple.

I met my kinlaws for the first time, yesterday. They seem like very nice people. I can see the resemblance between my kinlaws and their son, who is now my son-in-law.

At the wedding of my two friends, I could tell that the kinlaws were happy that their children finally married each other.