And Bob’s Your Uncle: A Guide To Defining Great Aunts, Great-Great Grandparents, First Cousins Once-Removed, and Other Kinfolk

When genetic counselors attend family reunions, their unofficial job becomes Namer-of-Relationships. “Keith, you and I are first cousins once-removed. Viola is my great aunt. Margo, you are my mother’s second cousin’s second wife so you would be…..well, some kind of in-law or kissing cousin, I guess.”  It gets confusing, even for experts. It is even more difficult for patients or referring providers who try to relate a family history of a second cousin with a cleft palate and a heart defect but who is actually a first cousin once-removed.

Below I have created a generic pedigree that illustrates the most common familial relationships in the kinship system of the modern Western English-speaking world. The pedigree undoubtedly contains errors and omissions. So, in the spirit of crowd sourcing, I encourage my fellow pedigree wonks to scrutinize it and report mistakes, mislabelings, missing relatives, and thoughtful commentary in the Comments section below (this would also be a great discussion topic for a few hours of a genetic counseling student seminar).

Click to Enlarge

Click to Enlarge

The accompanying explanatory table supplies details, controversies and inconsistencies. I am cowardly avoiding the complicated relationships that stem from assisted reproductive technologies such as donor eggs, donor sperm, surrogate mothers, etc. Of course, the person you decide to call Mother, Father, Uncle, Cousin, etc. is based not on genetic relationship but on personal experience, family preferences, and social norms.

For those not familiar with pedigree arcana, each individual is identified with a numbering scheme such that relatives in the first generation (at the top of the pedigree) are identified with a Roman numeral  (e.g., I) and an Arabic numeral (e.g., 2). This indicates, reading from left to right, that I-2 is the second person on the first line of the pedigree. The next generation down is numbered II, and so on. Thus, IV-7 is the seventh person in the fourth generation and who is the the proband or propositus, the reference point for the relationships. IV-7’s father is III-3, IV-7’s paternal great grandfathers are I-2 and I-4, and so on.

There seems to be no widely accepted guidelines for when to include hyphens in a relationship name (e.g., great-grandfather vs. great grandfather). Since this is my blog post, I get to decide the grammatical rules. Thus, because I tend to be a minimalist, I hyphenate only when there is more than one “great” in a title. In the pedigree, I-1 is a great-great-uncle, but I-2 is a great grandfather. I also use hyphens in “removed” relationships (e.g., first cousin once-removed) because, well, it just looks right. Stepmother seems to be more common than either step mother or  step-mother. However,  “stepbrother” is infrequent. For consistency, I recommend the spaced-but-not-hyphenated style for “step” and “half” descriptors” (e.g., half brother, step mother).

An alternative graphic to describe family relationships is the Canon Law Relationship Chart.

Image from Wikipedia Commons, under the GNU Free Documentation License.

Image from Wikipedia Commons, under the GNU Free Documentation License.

The relationships illustrated in the pedigree are described as follows:

Self, You, (AKA Proband, Propositus): IV-7, the person who is the reference point for  all relationships in the pedigree.


Genetic Father: III-3

Genetic Mother: III-4

Step Parent: III-5, the new or former spouse of your genetic mother or father.


Full Brother: IV-8. Male siblings with whom you share both genetic parents.

Full Sister: IV-9. Female siblings with whom you share both genetic parents.

Half Sibling: IV-10. A sibling with whom you share only one genetic parent. Or, as one of my patients said to me the other day “She is my half of a sister.”

Step Sibling: IV-11. A sibling with whom you share no genetic parents, e.g., the son  your stepfather had with his previous wife.


Son: V-2. A male child.

Daughter: V-3.  A female child.

Step Child: V-1. The son or daughter that your spouse had with a previous spouse.


Grandson, Granddaughter: VI-1. Your child’s son and daughter, respectively.

Great Grandson, Great Granddaughter: VII-1. The son and daughter, respectively, of your grandson or your granddaughter.


Grandfather: II-3, II-5. The father of your mother or father. But note the inconsistent use of grand and great. The brother and sister of your grandfather is your great uncle and great aunt (vide infra, Great Uncle, Grand Nephew). Presumably the word stems from the French grand-père, which itself goes back to the 12th century. Prior to the French influence, a grandfather was referred to as a grandsire, and prior to that, in Old English, the Germanic-derived ealdefæder or eldfader.

Great Grandfather:  I-2, I-4, I-6, I-8. The father of your grandparent.

Grandmother: II-4, II-6. The mother of your mother or your father.

 Great Grandmother: I-3, I-5, I-7, I-9. The mother of your grandparent.

Uncles, Aunts

Uncle: III-2, III-8. A brother of one of your parents

Aunt: III-1, III-9. A sister of one of your parents

Great Uncle: II-2, II-7. A brother of one of your 4 grandparents.  I thought about recommending the  less commonly used title Grand Uncle (or Grand Aunt) because these individuals are in the same generation as your grandparents. When they are referred to as Great relatives, it seems to imply that they are in the generation prior to your grandparents’ generation. I suspect, though, that Great is so well established that it is unlikely to replaced by Grand. And you share more genetic information with your Grandparents than you do with your Great Uncles, so perhaps using Great rather than Grand is an acknowledgment of that genetic difference (vide supra, Grandfather; vide infra, Grand Nephew vs. Great Nephew).

Great Aunt: II-1, II-8. A sister of one of your 4 grandparents

Great-Great Uncle: I-1. A brother of one of your 8 great grandparents. Note the slightly confusing terminology – the siblings of your great grandparents have two “greats” in their relationship title, compared to only one “great” in their sibling, your great grandparent.

Great-Great Aunt: I-10. A sister of one of your 8 great grandparents.

Nephew, Nieces

Nephew, Niece: V-4, V-6, V-5, V-7. The son and daughter, respectively, of your sibling.

Great Nephew (Grand Nephew), Great Niece (Grand Niece): VI-2, VI-3.  The son and daughter, respectively, of your nephew or niece. In genealogy circles, it is more common to use Grand rather than Great, on the basis that this relative is as many generations removed from you as your grandparent is, only in the other direction. However, in my view, if the siblings of your grandparents are Great Uncles and Great Aunts, then it seems to me that there is greater symmetry in calling them Great Nephew rather than Grand Nephew. Besides, you share as much genetic information with your Great Nephew as you do with your Great Aunt, so from that standpoint it makes more sense to go with Great rather than Grand (vide supra, Great Uncle, Grandfather.


First Cousin: IV-1, IV-2, IV-3, IV-4, IV-12, IV-13, IV-14, IV-15. The children of your aunts and uncles.

Second Cousin: IV-16.  The children of your parents’ first cousins.

First Cousin Once-Removed : V-8, III-10. The children of your first cousins OR the parents of your second cousin (who could also be properly called your second cousins once-removed). Once-removed refers to the fact that the relative is one generation removed from you, either one generation above or one generation below. The children of your second cousins could also be called your second cousins once-removed. This is one of the confusing areas where different relatives can have the same title and the same title could be applied to different relatives.

First Cousin TwiceRemoved: VI-4. The grandchildren of your first cousins.

Unnamed Relationships:

IV-5, III-6, III-7. As far as I am aware, in Western European kinship systems, there is no title for your spouse’s previous spouse IV-5), your step parent’s previous spouse (III-6), or the previous spouse of your step parent’s previous spouse (III-7).


Filed under Robert Resta

38 responses to “And Bob’s Your Uncle: A Guide To Defining Great Aunts, Great-Great Grandparents, First Cousins Once-Removed, and Other Kinfolk

  1. Jessica

    IV-10 appears to be a step-brother, not a half-brother.

  2. Quite a timely article as I’m teaching a pedigree workshop for my non-geneticly trained co-workers today. This will be a great addition to the Oscar & Lonzo “I’m my own grandpa” pedigree challenge I have lined up for them. Love your articles.

  3. Jade

    Hi Robert –

    These would be great to refer to during a confusing session. Any way we can get the images larger (better resolution)? Or downloadable via pdf?


  4. Robert Resta

    I thank Jessica for pointing out my full error about the half brother. I have updated the pedigree accordingly. It is always amazing to me how easy it is to make and miss clerical errors.

    I am not sure how to get the image any larger or clearer (though clicking on the pedigree itself will help some). I am happy to share a jpeg file, or, if you use Progeny, I can send the Progeny file. I only ask that you acknowledge the source and do not use it for commercial purposes.

    Bob Resta

  5. JB

    Excellent pedigree and explanations!

    It reminds me of the time when my father’s niece had a child and I asked “does this make me an uncle?!” A much younger me was quite deflated to learn that my paternal first cousin once-removed is not my nephew.

    I have wondered whether it may be useful to have two different terms to describe the two different types of first cousins once-removed. Although, not referring to the children of your first cousin as your second cousins (or your nephew) is a good start.

  6. KS

    I’m wondering how other describe which great grandparent (e.g. maternal great paternal grandmother — is that the correct way to say mom’s dad’s mother?).

  7. Robert Resta

    To JB, who wonders about a term to distinguish between the two different kinds of first cousin once-removed. I have seen some genealogists use the terms “ascending” and “descending” to differentiate between the parent of your first cousin and the child of your first cousin, respectively (e.g., first cousin once removed ascending). It seems like a reasonable nomenclature to me.

    To KS, I don’t know of any terms in Western kinship systems to differentiate among these “great” relationships, probably because there’s not much call to refer to those relatives during regular social intercourse (except maybe during the peculiarly weird intercourse of genetic counseling). I am guessing I know what drives your question; patients will not uncommonly say something like “My great grandmother had breast cancer” but don’t realize that they have 4 great grandmothers, and you have to carefully walk them through the relationship on a step by step basis.

  8. Shannon


    Is my mother’s half sister my half aunt? And are her children my half-cousins?
    My patients lately have been reporting lots of half aunts/uncles and cousins. I am wondering if anyone else is hearing these terms.


    • Robert Resta


      Yes, your mother’s half sister is your half aunt and her children are your half first cousins (just as Charles Darwin and Francis Galton were half first cousins since they shared a common paternal grandfather, Erasmus Darwin, but had different paternal grandmothers), by most standard nomenclature. Note that “halfs” would be one degree of genetic relationship further from the proband than “fulls,” e.g., a first cousin is a third degree relative but a half first cousin is a fourth degree relative.

      In my experience, many patients and healthcare providers confuse the terms “half” and “step,” which may partially explain why patients are reporting it to you. Half relatives are genetically related to the proband, while step relatives have no genetic relationship to the proband. It is helpful to “walk” the relationship with the patient, e.g., “So is this half first cousin your mother’s half brother’s genetic child (which would be a half first cousin), or is it your mother’s full brother’s wife’s child from a previous marriage (which would be a step cousin, I guess)?”

      Of course, many societies have very different and complex ways of describing familial relationships, so be particularly careful in using any of these terms with non-Westernized patients. Anthropologists have made whole careers of describing and exploring alternative kinship systems.

      • Annette Lee Zehring

        My grandmother had a half brother twenty years younger than she. What relationship to me is this half brother’s son? A second half-cousin?

  9. yes, it is very easy to make mistakes…say or write one thing when you mean another…for example, under 1C 1R, you say the parents of your 2nd cousin “could also be properly called your 2C 1R”…this is wrong…the parent of your 2nd cousin is the 1st cousin of your parent, thus your 1C 1R and nothing else…removeds are reckoned down, older generation to younger, not up…is your uncle your 1C 1R, being the father of your 1st cousin?…nope…

    • Robert Resta

      Like stolf, I was raised to believe that once-removed referred only to antecedent generations. However, after looking at genealogy texts, articles, and websites I found multiple instances of “removed” referring to preceding and succeeding generations. Indeed, some have suggested using the modifiers U and D in parentheses to indicate if the “removed” refers to previous generations or to later generations.

  10. Robert, you misunderstood me. Removed cousins are reciprocal, as are all kinship relationships…I am something to you, so you are something to me. And there is a way to distinguish two 1C1R…”ascending” for for older generation and “descending” for the younger generation is pretty much standard, altho I’ve seen up/down, backwards/forwards, major/minor…even one family that used augmented/diminished…which in time evolved into demented!

    My point is that the relationship is figured going downwards, since the older generation was there first. Take your father’s cousin. He is once removed because he is your father’s generation. But what degree of cousin? Down from his generation to yours it’s 1C1R, since he is part of your father’s generation as a 1st cousin. He is that to you and you are that to him. If you were to go up from your generation to his, then it is his son, your 2nd cousin, who part of your generation…so your father’s cousin would be your 2C1R…that is wrong and that is the mistake you made.

    As I mentioned, going younger to older generation, your uncle would also be your 1C1R, being the father of your 1st cousin…which is absolutely wrong…both your father’s brother and your father’s cousin would now be your 1C1R…what sense does that make? BTW, I’ve made this mistake in the past as well…it’s easy to do unless you have a really firm grasp on what the heck removed cousins are in the first place!

  11. Cathy Jacobs

    I recently was told that after my paternal grandfather’s (Clint) dad (Lloyd) died, his mother got remarried . . . to her late husband’s cousin (Arthur).

    Would I be correct in saying that in addition to Clint being Arthur’s stepson, he would also be his cousin once removed?

    Thank you.

  12. Cathy Jacobs

    Correction. My uncle e-mailed me that Arthur was my grandfather’s “second” cousin, so now I’m even more confused as to what relationship Arthur and Clint had other than stepfather/stepson. LOL

    Kudos to you, Bob, for having a website like this. I would have nightmares about family relations!

    • Robert Resta

      Well, this one kinda’ gives me a headache too, and I would have to know the exact connections between everybody, but as I read it and think I understand it, Clint is Arthur’s second cousin once-removed and your second cousin thrice-removed.

      • Cathy Jacobs

        Thanks so much for your reply, Bob. Your conclusion works for me!

        Talking about headaches, I thought you’d get a kick out of four more examples of my crazy family relationships (no questions . . . just wanted to make you smile).

        Arthur (Grandpa Clint’s stepfather) had a sister, Mae, who married a “Vargason.” Arthur’s stepson (Grandpa Clint) also married a “Vargason” — my paternal grandma, Madge Vargason Benjamin Kishpaugh. I don’t know yet how Grandma Madge was related to her “first husband’s stepfather’s sister’s husband,” and I don’t think I want to (although if you’re ever bored, you might want to figure it out!)

        My paternal grandmother (Madge) divorced my paternal grandfather (Clint), and married Walter Kishpaugh. When my parents split up, my dad married Walt’s youngest sister, my late stepmother, Barb. This makes Madge and Walt both my grandparents and my aunt & uncle. It also makes my stepmother, my father’s step-aunt.

        Walt and Barb’s dad, also a Kishpaugh, got his wife LoRena’s sister, Isabelle, pregnant (hopefully, this was after LoRena’s death in ’43), which makes that offspring both a brother and a cousin to Walt, Barb and their other two siblings.

        On two occasions, LoRena’s mother, Lena Lerche, gave birth to sons she couldn’t keep. One boy was adopted by Lena’s brother, George Kinney; the other boy was adopted by her brother, Willis. So, brothers who started out as “Lerches,” ended up cousins named “Kinney.”

        Thanks again for helping me, Bob; I really appreciate it. I think I’ll bookmark your website, as the questions people ask you are very interesting.


  13. R Boleyn

    I’ve read about double cousins, but what is the relationship in this case: A man marries a woman and has a child. He then divorces her, and marries her sister and has a kid.
    Are the two kids half siblings (paternal relationship), or cousins (maternal relationship), or something entirely different, like double half-sibling cousins???

    • misskitty79

      The answer to that, I think, will be twofold. There’s the technical genetic connections (which makes them BOTH half brothers *&* cousins), but the question of which term will be more socially acceptable… I propose that, if both children continue to live w/ the father, they’d likely be considered half-brothers, but if the child from the first marriage remains w/ the first wife, then they’d probably only be referred to as cousins.

  14. Help, please….

    Much to my dismay, I have discovered my ex and I are 13th cousins 2x removed. (royal lineage connection). Oh snap.

    Trying to figure out our sons relationship to one particular ancestor.

    She is my 15th cousin and my exes 14th cousin 1x removed.

    What would my son’s relationship be to this common ancestor?

    Thank you so much!

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  18. Terry Maurice


    With all due respect to your otherwise excellent writing, why do you continue to complicate the naming of uncles and aunts by using the “great” uncle/aunt terminology when referring to the siblings of one’s grandparents as great uncles and great aunts. Although widely used, it is simply wrong and only adds to the confusion.

    The siblings of grand parents are grand uncles and grand aunts. It is simple and easy to remember. The siblings of one’s great grandparents are great grand uncles and great grand aunts. It is consistent with how one’s grandparents are named and also with how nephews and nieces are named and avoids the confusion that using only great creates. Just because a lot of people use the great uncle/aunt does not make it right.

    Furthering the use of this erroneous terminology as you have done in your article just continues the confusion. Someone has to straighten this out sooner than later. Why not sooner!

    • Robert Resta

      You raise an interesting question for me. Who decides what is the “right” and the “wrong” term for a particular familial relationship? Who sets the rules? As I’ve explored familial relationships over the years, I’ve found that there are many differing views as to what should be standardized nomenclature for pedigree relationships. I can be right in one system and wrong in another. Indeed, my blog post contributes to that variation. For me, the variety may be the most interesting part of all this.

      • Terry Maurice

        Yes, right and wrong is perhaps a bit rigid, but we should not let common useage create a situation that is confusing for all concerned. Using grand uncle or grand aunt terminology is consistent with the accepted naming of grandparents. In my opinion, using great rather than grand only creates confusion, especially for those new to or unfamiliar with genealogical terminology. Our goal should be clarity rather than confusion.

  19. well, genealogical convention decides the “rules,” at least the correct kinship terms to use in English…that’s simply so everybody knows what they’re talking about…”2nd cousin” is a perfect example…i see that, and i wonder: do they mean (rightly) somebody of your generation, that is, the grandchild of a grandparent’s sibling?…or do they mean (wrongly) somebody one generation removed (REMOVED!) from you, that is, your parent’s 1st cousin or your 1st cousin’s child…unless there are other “clues” to what they mean, they might as well not have said anything…that’s plain old common sense communication…

  20. BTW…stolf = Mark Astolfi…as to the great “grand/great uncle/aunt” debate…Terry is right of course…the difference here is, using one or the other does NOT cause miscommunication…there is no ambiguity or confusion as to what you mean…the reason genealogists prefer it the way Terry described is pure practicality…going back many generations, it makes more sense for 2 siblings to both have 1 grand and 6 greats…than for one sibling to have 1 grand and 6 greats and the other to have 7 greats…and notice that the parent of those siblings also has 7 greats…like one of his children, but not like the other…huh?…

    bottom line: you don’t have a great uncle because you don’t have a great father…ever notice that?

    • Robert Resta

      While I don’t disagree with any of the grand, great, and removed points you have all made, saying that “genealogical convention” is the Great Judge begs the question: Which genealogist? Which convention? Who has “final authority” and why? Multiple genealogical resources that I have consulted over the years have given different definitions of various relationships, usually with certain authority.

      • different definitions of what relationships?…except for the great/grand uncle/aunt thing, i can’t think of one area of disagreement…can you supply one?…granted, some definitions may be stated in different ways, but they amount to the same thing…otherwise, how could genealogists talk to each other?

  21. Robert Resta

    Here are a few examples of different views on nomenclature. I agree that clarity, consistency and internal logic are all called for, and critical for communication. This discussion also raises the issue of distinctions between kinship systems and genealogy systems.

    1) While the Child of your second Cousin is your second Cousin once removed – being one generation removed from yours – the Parent of your second Cousin is ALSO your second Cousin once removed – because they are one generation removed from your generation as well.

    2) GRANDAUNT/UNCLE: The siblings of your parents are your aunts/uncles. The siblings of your grandparents were originally termed grandaunts/uncles and the siblings of your great-grand parents were great-grandaunts/uncles. But over the years those terms have gradually been replaced by the less de-scriptive great-aunt/uncle for grandaunt/uncle and great-great-aunt/uncle for great-grandaunt/uncle.

    3) See this chart on American Kinship Terminology (not great quality and requires a bit of squinting):

    4) The genealogical term ‘removed’ means to move up or down generations.
    ONCE Removed means move up or down ONE generation
    TWICE Removed means to move up or down TWO generations,_'Removed

    • Terry Maurice

      Robert The first example is not correct. The parent of your second cousin is your first cousin once removed, not a second cousin once removed. Your parent and your second cousins’ parents are first cousins, which makes you the first cousin once removed to your parents’ first cousin.

    • Tom Anderson

      Bicknell is incorrect to say that the original term was grandaunt/uncle. The term greataunt/uncle were used in publications 200 years prior to the appearance of the new more logical terms.

  22. Can you post a higher quality version of the chart? I’d like to show this to a friend, but I think they’d get annoyed trying to read it and miss the awesomeness. Thanks!

  23. Robert Resta


    I have been working on producing a higher quality graphic of the pedigree, but it turns out to be not as easy as I thought it would be. But I will keep at it and hopefully produce a better quality image to share..

  24. Mike

    If my great-grandfather and my girlfriends’ great-grandfather were double cousins, what does that make us? What percent of genetics would we share? Came to find out her moms maiden name is the same as my last name, kind of got weirded out. Are we genetically far enough apart for it to be “acceptable” and not have any complications?

  25. After reading this, I want to verify if I have figured correctly the relationship I am seeking. Is my great-grandfather’s nephew my first cousin TWICE REMOVED? Additionally his mother (my great-grandfather’s sister) is my great-great aunt, is she not?

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