What is a 2nd great-aunt or 2nd great-uncle?
Short answerYour 2nd great-aunt or uncle is a sibling of your great-grandparent. You are their 2nd great-niece or nephew: the great-grandchild of their sibling. You share 2nd great-grandparents, and a full 2nd great-aunt or uncle shares about 6.25% of your DNA on average.
The family line, drawn out
Follow the highlighted line from you up to the shared ancestor and down to them.
How to work it out
Go up 4 generations from you to a shared 2nd great-grandparent, then 1 down to their child. That child is a sibling of your great-grandparent, which makes them your 2nd great-aunt or uncle. Some genealogists write 1st grandaunt or great-grandaunt instead; all name the same person.
Their spouse or partner is your 2nd great-aunt or uncle by marriage. Their children are your first cousin twice removeds.
What to call each other
| Them, to you | You, to them | |
|---|---|---|
| Female | 2nd great-aunt | 2nd great-niece |
| Male | 2nd great-uncle | 2nd great-nephew |
| Anyone | 2nd great-aunt or uncle | 2nd great-niece or nephew |
Their family and yours
Relationships shift by one step for each generation. Here is how the people around them relate to you:
| Their child | first cousin twice removed |
| Their parent on the shared line | 2nd great-grandparent |
| Your child sees them as your child’s | 3rd great-aunt or uncle |
| Your parent sees them as your parent’s | great-aunt or uncle |
| What they call you | 2nd great-niece or nephew |
Shared DNA
On average, full 2nd great-aunts and uncles share about 6.25% of their DNA. That figure is the expected value: it halves with every generation of separation, and real amounts vary from person to person. A half relationship (through only one shared ancestor instead of a couple) shares about half as much: 3.12%.
Let Family Trees name it for you
In Family Trees, open anyone’s page to see how they are related to you in plain words, or choose any two people under How are they related?. The app counts the shortest blood line through birth and adoptive parents, names step, foster and in-law relations too, and uses exactly the words on this page. It’s free for a family of up to 100 people. You can also try the relationship calculator here.
Questions
What is a 2nd great-aunt or uncle?
Your 2nd great-aunt or uncle is a sibling of your great-grandparent. You are their 2nd great-niece or nephew: the great-grandchild of their sibling.
How much DNA do you share with a 2nd great-aunt or uncle?
About 6.25% on average. Each generation of separation halves the expected amount, and individual results vary.
What is my 2nd great-aunt or uncle’s child to me?
Your first cousin twice removed.