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I've come across two third cousins, who are third cousins through two different routes as the same two families had two separate marriages between them that leads to this situation.

I was thinking perhaps calling them double third cousins, but would like to know the official terminology.

You can see an example of this relationship here. Notice that there are two sets of married ancestors, the Brown/Hodges marriage and the Brizendine/Cochran marriage, both common relations make them third cousins. See popup menu that allows navigation among the four common ancestors in this screenshot:

Screenshot of popup menu for selecting which of the four common ancestors to view the connection through

Harry V.
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WilliamKF
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  • http://www.genetic-genealogy.co.uk/Toc115570138.html says that there are "9 possible types of double third cousins". – PolyGeo Jan 21 '17 at 06:21
  • Are you able to include a family tree that illustrates this relationship? It does not need to include names, and if anyone in the tree was born less than 100 years ago I think they should be made anonymous. – PolyGeo Jan 28 '17 at 22:59
  • I've looked at your WikiTree page and can see lots of interesting information there. However, I think it would still be more useful to see a family tree which has the two sets of 2nd great grandparents at the top and traces them through each generation to the double third cousins at the bottom (both ways). – PolyGeo Jan 29 '17 at 08:24

1 Answers1

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I think that you are using the correct term of double third cousins.

Two individuals are third cousins when they share a single pair of 2nd great grandparents.

Since your individuals share two pairs of 2nd great grandparents they are double third cousins.

From "Genetic and Quantitative Aspects of Genealogy" (F. M. Lancaster; Oct 2005, updated Feb 2015) I learned that:

there are 9 possible kinds of double third cousins

From my quick look at that paper it seems like there are many relationships possible, but fortunately for this one the simple term of double third cousins is available.

PolyGeo
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