From the Department of There Ought To Be A Word For That.

When Arabella is Brenna’s cousin and Brenna is Carolyn’s cousin, what are Arabella and Carolyn? They’re not related, let’s say. Let’s suppose Arabella’s mum is Brenna’s mum’s sister, and Carolyn’s mum is Brenna’s dad’s sister. Let’s also assume no inbreeding. Then Arabella and Carolyn share no ancestors at all, so by definition they’re not cousins of any degree. (Except in the trivial sense wherein everyone is related and they might be, like, 34th cousins.)

I can’t remember where this term came up, but I like co-cousins. Arabella and Carolyn are co-cousins. They share Brenna as a cousin. To Brenna, they are both cousins.

Why do I think co-cousins ought to be a word? I know several of my co-cousins pretty well. In fact, I probably saw them more often than some of my actual blood-related cousins, due to the way my relatives are networked geographically. For technical reasons I can’t refer to them as cousins (even though for the longest time I thought they counted as cousins!), but I find referring to them as Unrelated Friends of the Family to be unsatisfying. Of course they’re related, just to other members of the family tree!

(It’s weird that X is related to Y is not transitive. Arabella is related to Brenna, and Brenna is related to Carolyn, but Arabella is not related to Carolyn.)

So this kind of indirect familial relation deserves a name. I haven’t heard any better names, so co-cousin it shall be.

Other genealogical terms that I made up and I am fond of: cousin cohort (the set of all of someone’s grandchildren), second cousin squadron (the set of all of someone’s great-grandchildren), and third cousin tribe (the set of all of someone’s great-great-grandchildren).

I am a member of two cousin cohorts: one with my maternal cousins, corresponding to my maternal grandparents, and one with my paternal cousins, corresponding to my paternal grandparents.

Oh gosh. I hope I will have grandchildren someday.