Cousins Chart: Understanding Your Family Relationships

Having trouble coming up with the proper term for your mother's uncle's father for your family tree? Here's a guide to who's who in the family structure.

Second cousin twice removed. Sounds mathematical, as though establishing a family relationship required the use of trigonometric algorithms. But like so many apparently daunting areas of expertise, it's really just a matter of learning the lingo. In the definitions below, "you" serve as the frame of reference, around which all the other relations revolve.

Uncle and Aunt

Your parents' brothers and sisters, and their spouses. You don't need any blood connection to be a full-fledged aunt or uncle. Your mother's sister's husband is not your uncle by marriage. He's your uncle, fair and square.

Niece and Nephew

Son and daughter of your siblings and siblings-in-law. As with uncle and aunt, they're not your nieces and nephews by marriage, they're your nieces and nephews, plain and simple, even if they're your spouse's siblings' kids and don't have a single drop of blood in common with you.

First Cousin, Full Cousin, Cousin-German

Children of your parents' brothers and sisters. You and your first cousins share one set of grandparents.

Double First Cousins

If a pair of brothers marries a pair of sisters, their kids are not only first cousins, they're double first cousins: They have both sets of grandparents in common.

Second Cousins

You and the children of your parents' cousins are second cousins and share at least one great-grandparent. Your child and your cousin's child are second cousins.

Third Cousins

You and the children of your parents' second cousins are third cousins and share at least one great-great-grandparent. And so on with the fourth, fifth, and sixth cousins.

First Cousin Once Removed

A relationship that is removed is one that exists in two different genealogical generations. Generation refers to the order of birth, a genealogical level. Your aunt and your mother may have been born 20 years apart, but they are still of the same generation. Your parent's first cousin is your first cousin once removed. The child of your first cousin is also your first cousin once removed: your grandparent is that child's great-grandparent. You can do the whole "removed" thing for every category of cousins—second cousin once removed, and so on. But by then you'll probably drive everyone completely crazy.

Grandaunt and Granduncle

We always called grandpa's sister "great-aunt." But the experts say that terminology is incorrect, and the terms above should be used instead to refer to the siblings of your grandparents. (Which doesn't mean we have any intention of using them.)

Great-Grandaunts and Great-Granduncles

Your great-grandparents' brothers and sisters.


Family by marriage: Your spouse's parents, spouses of your siblings, and spouses of your spouse's siblings. That is, your brother's wife is an in-law, but none of her siblings are. And your husband's sister's husband is your in-law, but none of his brothers are. And in-laws pretty much stop with your parents-in-law and your siblings-in-law. You are not in-laws with the parents of your sister-in-law's husband. And the two sets of parents of a couple are not in-laws to each other either; they are the competitive parents—an entirely different category.

Affinity Relatives

Your husband or wife's blood relatives -- the in-laws that are biologically related to your spouse.

Birth Mother, Biological Mother, Natural Mother

Terms for the biological mother of a child who has (usually) been adopted by other parents.

Adoptive Mother

Mother of a child who is not biologically her own.


  1. what would my mother's cousin's daughter's son be to my daughter

    1. Your mother’s cousin shares a grandparent (or grandparents) with your mother.

      You share GREAT grandparents with mom’s cousin’ children - you are their SECOND cousin.

      YOUR children share GREAT GREAT grandparent(s) with the children of your second cousin - they are THIRD cousins.

  2. My Uncle (from Mother side) has a child named Rob. Rob has a cousin named Don (from the side of the wife of my uncle). What is my relationship with Don?

  3. My moms uncle is my teachers father what is my teacher to me??

    1. first cousin once removed

    2. The teacher is your moms cousin, so the teacher is your 1st cousin once removed.

    3. 1st cousin. Children of siblings are 1st cousins

    4. Your cousin

  4. Please help... What would my 2nd cousin 3 times removed's son be to me? (None of the charts I can find go that far...)

    1. Hmm assuming you are calculating it correctly. That would just be a 2nd cousin 4 times removed. You second cousin's great-great-great grandchild?

    2. One more 'removed' since it is a direct descendent of the 2nd cousin.

  5. My dads sister is married to my 3rd cousin. What is the relationship between my dads sister and my 3rd cousin?

  6. If my father’s sister marries my mother’s first cousin and they have children, what relation are they to me?

    1. Actually, your moms 1st cousin is your 1st cousin once removed, so I think they would be both 1st cousin and 1st cousin twice removed.
      I would think the closest relation of the 2 would be how you would address them in relation to yourself.
      But both terms are important for defining relationships of your kids to them and their kids.

    2. Your father's sisters kids are your first cousins. Also, your moms first cousins kids are 1st cousins once removed. At the same time!

  7. So my uncle married a woman who had kids already. One of her daughters seem's interested in but I dont know if that would be messed up to in a relationship or not? Were related by blood. I think its considered second cousin in law maybe?

    1. I believe she would be your step-cousin once removed.
      She is your uncles step daughters daughter. Or your step cousins daughter which would be once removed.

    2. It wouldn't be a legal problem, but the religion, morals and taboos in the family would dictate how your family might respond... Anything beyond that is all in your pro vs con analysis of what to do next.

    3. We are not related by blood but by marriage

    4. I mean one of her daughter's daughter. Likes me alot. Not her daughter but my aunt in law grandaughter

  8. This guys step dad is my uncle, what is he?

    1. Step cousin

  9. So my cousin met this girl and then he got her pregnant they have a kid together but the girl and I have been off and on for years am I wrong to be with her

  10. My moms cousin is called my “ uncle” is that what he is?

    1. Your mothers cousin would actually be your 1st cousin once removed. However, "uncle" is a perfectly respectful title...

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