What Do You call Them?

[darkerhorse]

You're father's parents are your paternal grandparents.

What would you call your father's paternal grandparents?

What would you call your father's maternal grandparents?

[PippoM]

I can tell you my experience, though I'm not a reliable reference for English.
Once, I did a research job, and used the term "maternal paternal GF" to mean the paternal GF on maternal side, and was not corrected, nor asked what I meant. However, maybe the agency corrected my text before providing it to the client.

[darkerhorse]

Thanks for your reply.

I was thinking along those lines, too. But it gets very wordy as you go back generations.

[rp76226]

Either way, they are all still your paternal great grandparents. All of their ancestors are still paternal grandparents to you.

All of your mother's parents, grandparents and their ancestors are still maternal grandparents to you.