What term is appropriate when naming "in-law" relationships?

Are my parents called "grandparents" or "grandparents in law" to the children of their son-in-law's brother? Or is it something else?

What term is appropriate when naming "in-law" relationships?
Technically, they are neither. There is no family relationship across the in-law line. In other words, my brother's wife is my sister-in-law. But her sister is not related to me. I could loosely call her my sister-in-law, but it would be a misnomer.





In these cases, especially when it comes to a grandparent and young children, the grandparents often encourage the use of nicknames like grandpa, grandma, pappy, mangu, etc etc and I don't see anything wrong with it.
Reply:I would just keep it at grandparents, i don't think I've ever actually heard "grandparents in law" being used, it sounds weird to me. Grandparents are fairly distant relatives compared to brothers, sisters, etc, so I don't see a problem in just leaving it at grandparents. Not like there's different roles in "grandparents" and "grandparents in laws" anyway. ;)
Reply:When you get married, both families blend, so saying "grandparents" is appropriate, or you can say, "my husband's grandparents" too.