You have first cousins, second cousins, cousins thrice removed that share a common ancestor through one family line. You can even be a first cousin, as well as a second cousin, to the same person depending on the different family lines connections. But I'm curious about what we call our ancestors.

If you have an ancestor that is connected to your family lineage multiple times, through different lines, is there a special designation for that relationship?

Random Eg your paternal greatx7 father is the same man as your maternal greatx7 father. Or paternal greatx7 father is the same man as your maternal greatx7 father AND maternal mother's greatx7 father. The examples go on and on (and don't forget about the more incestuous relationships).

Are they your great X 7 father X 3? Third degree? Raised to the third?

More simply. Brother and sister marry. Your dad is your partners dad and any kids you have will have the same grandfather twice. Aunt marries nephew. You dad is you partners grandfather and any kids you have will have the same man as both their grandfather and great grandfather.

And what happens when there is a generation mismatch: when the common ancestor is in generation 7 in one line and generation 8 in another?

CLARIFICATION EDIT: the answers so far have provided very helpful information, unfortunately not exactly what I was asking. Maybe I muddled up my written question.

I'm not asking how to describe the exact lineage of an ancestor eg John Smith is your mother's father's fathers mothers fathers mothers mothers father. Looking at the answers provided, that seems to be pretty well documented with numerous different systems that all have their pros and cons (some very interesting ideas out there).

I investigating if there is a simple notation I can add to a relative's name/ family designator to say they connect to 2, or 3 or more lines. I can then choose to look in more detail at that persons notes etc to figure out the exact different relationships. This would reduce the number of detailed lineage abbreviations I would have to add to the end of some ancestors entries on my tree, if they connect multiple times.

I have attempted to answer my own question. Please have a look.


I haven't seen such terminology.

But I needed something similar, mainly to define DNA relationships, so I developed a notation I call: Behold's Genetic Relationship Notation (BGRN).

You can develop relationships in words from the notation, e.g.:

Y- = Male person’s spouse 
Y-(YX)xaY = Male person’s spouse’s sister’s adopted child’s father. 
XXXX–x-X- = Female person’s mother’s mother’s mother’s spouse’s daughter’s spouse’s mother’s spouse. 
Y(YX)xy(Y)y-(YX)x- = Male person’s sister’s son’s paternal half-brother’s spouse’s brother’s spouse.

BGRN should be able to handle any relationship, no matter how complicated.

For people related multiple ways, I would show one string for every relationship. That way, for DNA purposes, the percentages of DNA calculated for each string can be added to get the average expected DNA match between the two people.

In the case of one of your incestuous relationships, e.g. Your dad is your partner's grandfather, I'd list two relationship strings:

  1. U- = your partner
  2. U(Y)uu = your father's child's child

See my blog post on BGRN for all the details.

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My understanding is that if there are two ways for one person to be related to another, then that is called a double relationship.

To determine what each of the two individual relationships may be called we have a Q&A here that can be used: Seeking English term for relationship between two members of extended family?

The other Q&A here that I think can be very helpful in the generic context of your question is How to determine relationship with a cousin?

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  • 1
    I'm not so much asking what you would call them in typical everyday life. Half brother, step sister, adopted father. I'd call them brother, sister, dad...unless I was upset with them. But I'm more interested in a standard systematic method for noting the relationship degrees and relationship 'concentrations'. So someone is my great great great grandfather, but on paper he is my greatx3 grandfather to the nth degree?! Something like that. – EveryBitHelps Oct 31 '16 at 21:48
  • Try stevemorse.org/relation/calculator.html which is in one of the answers to the question that I linked to. If you don't think that my answer and that resolve what you are trying to ask perhaps focus your question on a single example, rather than the many it currently contains, so that I and any other potential answerers can explain why I/we think it should. – PolyGeo Oct 31 '16 at 22:08
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    Bear in mind that you have (potentially) 512 8xGGFs. Any system aiming to describe this in words would need to specify which. Unless someone wants to challenge me, there is no such naming convention. As I recollect, there are various numbering systems that would specify exactly which position on the ancestral tree is referred to. Someone who is doubly related would have 2 such numbers. – AdrianB38 Nov 1 '16 at 0:34
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    If I'm understanding the question properly, the user is asking for a mathematical or faux-mathematical estimation of the amount of pedigree collapse for a particular individual. – Jan Murphy Nov 1 '16 at 18:10
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    @Jan Murphy, I've tried to clarify the question, and have written an answer with what I have been thinking of. I believe I'm looking for a mathematical way of showing a simple measuring convention – EveryBitHelps Nov 2 '16 at 21:55

I'm going to attempt to answer my own question to get comments and feedback on the solution I have been thinking of.


  • this system would be based on the entire family tree currently being worked on.
  • it would only show that an ancestor/individual had multiple different descending branches that connected at a later date
  • It wouldn't be specific to a specific descendant to ancestor relationship so it wouldn't be reliant on labelling your mothers, fathers, mothers, fathers aunts, father etc.
    • this is purely for at a glance notation. that you don't keep looking up if the John Smith born in 1700 on your fathers tree is the same J. Smith born in 1700 on your mother's tree.

SAME GENERATION: Instead of having multiple annotations for the different lineage routes that an ancestor shares, you can use a simple exponent symbol

eg John Smith ^x

where x is the number of times they connect to different lines in the same generation

There could be several different ways this could be written depending on the software you use:

  • John Smith ^2
  • John Smith ^3 (Superscript)
  • John Smith is your gggggggf^2
  • John Smith ^2 is your gggggggf

DIFFERENT GENERATION MISMATCH: For an ancestor that connects over different generations. I'm thinking of a simple +/- sign infront of two extra digits for the proceeding (younger) or preceeding (older) generation

eg John Smith ^x,-y,+z (very incestuous)

where y is the number of times they connect to different lines in the younger generation and z the number of times they connect to different lines in the older generation than the first entry x.

this would mean that:

John Smith ^3,-2,+3 is your

  • gggggggf three times,
  • ggggggf two times (younger generation) and
  • ggggggggf three times (older generation).

TWO GENERATION MISMATCH: If there happens to be a two or more generation mismatch you can have multiple +/- signs to indicate the difference from the first digit x.

eg ^x,--y,-y,+z,++z

SIMPLIFICATION: I not sure if there would be many instances where an ancestor is the same across three generations, but I expect that 2 generations may be fairly common. You could simplify it to:

  • John Smith ^3,+3
  • John Smith ^3,--2

If you happen to have a single value for a generation mismatch you could just show the +/- signs

  • John Smith ^3,+

On investigating you could see that John is your ggggggf three times and one time is also your great ggggggf

Deciding which family line to designate as the first number would be personal preference. It could depend on which connection was found first or if personal preference requires it that your 'main' branch should go first. I assume using the +/- would also depend on which connection was recorded first, unless personal OCD preference requires all notations to be youngest to oldest.

If your software allows it, using a superscript may also further reduce annotation clutter.

You can then see at a glance that this ancestor has multiple lines that connect later in time, and you can go and investigate further for the exact path.

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  • OK, I believe that I understand now. A shorthand notation to say that someone is, say, my 4GGF and my 5GGF at the same time. And nothing more than that. I know of nothing but that doesn't mean that some process might not do it. Personally I'd just write what I just did against that one pair of ancestors and leave it at that. It's a balancing act between clarity for the reader and brevity for the author. It's also getting subjective... – AdrianB38 Nov 3 '16 at 9:41
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    I use Ahnentafel numbering as the base of my own numbering system, which identifies all relatives and their closest line of descent. One of my ancestors has the sequence "386 &834 &850 &882" -- showing he is at the head of 4 different lines. 512 is the start of the 10th generation (7th great-grandparents) so the sequence shows that one line is 1 generation closer than the others. Comment rather than answer because my system may not be a match to the OP's requirements. – bgwiehle Nov 4 '16 at 15:44
  • @AdrianB38, yeah the method I am thinking of would be subjective, but I was asking if there is already some sort of existing system for this. So the question isnt so much subjective, as checking if it's even necessary to come up with a subjective method :) – EveryBitHelps Nov 4 '16 at 20:04
  • Question isn't subjective and I doubt that the method would be. However what I was trying to say was that the advantages of one notation over another might very well be subjective. Though hard to demonstrate that without some methods to compare.... Ahnentafel numbering - or rather, having multiple such numbers seems 1 way but the legibility of such numbers depends very much on the personal circumstances of the reader - i.e. is subjective. – AdrianB38 Nov 4 '16 at 20:15
  • @AdrainB38, definitely agree on that. – EveryBitHelps Nov 4 '16 at 20:41

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