Genealogy 101: Understanding Family Tree Relationships

A family tree is an excellent visual tool for exploring your family genealogy. Whether you are retracing your heritage for a school project or wanting to learn more about your family, researching your family tree history can help you uncover a deeper understanding of who you are and where you came from.

Illustration: the family tree of Sigmund Christoph von Waldburg-Zeil-Trauchburg, late 18th century
Illustration: the family tree of Sigmund Christoph von Waldburg-Zeil-Trauchburg, late 18th century. Credit: Wikimedia Commons.

Despite the seemingly simple concept of the family tree, there are specific genealogy and kinship terms that can be confusing to understand when starting your family tree research. With that in mind, we’re sharing this guide to explain the different family tree relationships.

Affinal v. Consanguine

When attempting to build anything other than your immediate family tree, you will inevitably run into some new terminology. “Affinal” and “consanguinity” are the two most important of these often-unfamiliar genealogy terms. Understanding their definitions is critical, as they will take you down two very different paths.

  • An affinal relationship is a kinship term meaning “by marriage.” On any family tree, an affinal relationship is signified by the term “in law.”
  • Consanguinity is translated directly as “of the same blood,” or in other words, a blood relation. Your parents, (great) grandparents, uncles, aunts, brothers, sisters, and cousins of various degrees are all a part of your consanguine family tree.

When exploring your family tree history, it is important to make the distinction between those to whom you are bound by marriage and those to whom you are bound by blood. The rest of this guide will exclusively explore the blood relationships. However, you can just as easily apply many of the kinship terms used for blood relations to your spouse or partner by adding “in law” as a suffix to their title.

Genealogy Terms: The Great, Grand, and the Great-Great Grand

When constructing your family tree, it is essential that you consider the irreplaceable roots without which you would not exist: your parents, their parents, and their parents’ parents. Your grandparents can be the key to correctly placing your uncles, aunts and their children (your first cousins) into your family tree.

Great-grandparents and great-great-grandparents are often harder to trace, connect, and find a record of, as there are many branches of cousins that emanate from them. A great-grandparent is the parent of your grandparent and a great-great-grandparent is the parent of your great-grandparent.

Generations before great-great usually go by numerical terminology. For example: third great-grandparent, fourth great-grandparent, and so on. Using this terminology avoids an extended repetition of “great-great-great-.”

The generation gaps that exist between great-grandparents (and beyond) and ourselves can often lead to a loss of information and family records. As such, tracing these relatives can help you find other ancestors and expand the branches of your family tree.

Cousin Kinship Terms: Degrees and Removed

During family gatherings and your research, you may have heard the phrase “third cousin twice removed” and marveled that anyone could possess such a relation. It’s quite common to have third cousins twice removed, not to mention a whole slurry of other seemingly impossible family tree relationships.

Illustration: a chart illustrating the different types of cousins, including genetic kinship marked within boxes in red which shows the actual genetic degree of relationship (gene share) with “self” in percentage (%)
Illustration: a chart illustrating the different types of cousins, including genetic kinship marked within boxes in red which shows the actual genetic degree of relationship (gene share) with “self” in percentage (%). Credit: Gringer; Wikimedia Commons.

Degrees of Cousins

There are a few degrees of relationships with your various cousins to know when it comes to your family tree:

  • First cousins: those who have the same grandparents as you but are not your siblings.
  • Second cousins: those who only have the same great-grandparents as you.
  • Third cousins: those who only have the same great-great-grandparents as you.

The term “removed” is a signifier of how many generations apart you are from that specific cousin. For example, your second cousin twice removed is the grandchild of your second cousin, as they are removed from you by two generations.

Table of Consanguinity

While understanding and tracing all these relationships can be confusing, a table of consanguinity exists to save us all from the headache of counting our family tree relationships out. The table helps to take you step-by-step through your relatives, from your great-grandparents to your great-grandchildren and everyone in between. Establishing how everyone is connected can help you learn more about your ancestors and trace the different families in your family tree.

What’s Next? Build Your Family Tree!

A family tree can go back many generations and expand across many related families. However, tracing every relative and their records to help fill in all the details can be difficult. Memories fade, family records are lost, and stories are forgotten. After collecting as much information from your relatives as you can, use online genealogical resources to help you learn more.

Local newspapers published countless stories about the people in their communities. Many newspaper articles are the only remaining record of an ancestor. Use GenealogyBank’s Historical Newspaper Archives to research and get to know the people behind the names on your family tree.

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13 thoughts on “Genealogy 101: Understanding Family Tree Relationships

    1. Sorry I’m late to the party. That said, I devised a generational numbering system for identifying my ancestors, as well as other relatives and inlaws. I’ll be happy to explain if you are still interested.

  1. This is helpful info, but still does not address what I think is a more important issue for many of us: what term can be used to describe a half-sibling raised by a different family than the birth family? For instance, my half-brother was adopted and raised by a wonderful family. I value his relationship to my mother and my immediate family, and I value my (more tenuous) relationship to his family of nurture. Likewise, my mother’s mother was adopted. While I am researching what I can, I may never know her birth parents -– only her adoptive parents, and records indicating THEIR parents. What term should I use to describe that relationship?

    I can tell you that I value the loves, positive values and cultural contributions those non-birth parents have introduced to my family line. To varying degrees, they HAVE shaped my current family. I’m interested in their family lines and history as much as that of my blood relatives. Surely genealogists have developed some terminology to use for these relationships.

  2. What if a child is adopted and not blood, but you want them a part of your family tree and they are not an in-law? Thanks.

    1. That’s a great question, Beverly! “In the case of adoption, the ties of love are generally stronger than ties of blood…” (Quote taken from https://www.thoughtco.com/handling-adoption-in-the-family-tree-1421622) (Site visited Nov. 13, 2018.)

      I would recommend reading through that entire article. It will give you insights on different options for creating family trees involving adoptions.

      If you have an account at Ancestry.com, they’ve got a step-by-step guide on how you can list adoptive parents or adopted children in your tree on their site. (See https://support.ancestry.com/s/article/Listing-Adopted-Children-in-your-Ancestry-Member-Tree-1460091980271-3698)

  3. Excellent point, KWight! As someone who gained two older siblings by adoption, I can appreciate your comments. These relationships are priceless, and language should find a way to address this situation in a respectful manner.

    The following is an excerpt taken from FindMyPast (https://www.findmypast.com/content/adoption-records-and-genealogy)(visited Nov. 13,2018):
    “Your language requires a thoughtful approach. Certain words and phrases feel tainted with judgment to some people involved in the adoption process. Adoption professionals and social workers avoid potentially hurtful phrases by using Respectful Adoption Language. Especially if you are talking to adoption professionals during a search, it helps to speak their language.

    “It is more accepted to say a person ‘was’ adopted, not ‘is’ adopted. The process of legally joining a family took place in a courtroom long ago. Adoption is a legal process, not a condition.
    “‘Birth mother’ and ‘birth father’ replace ‘natural mother’ and ‘natural father’ to avoid implying an unnatural relationship between a child and adoptive parents.
    “Birth families ‘make an adoption’ plan rather than ‘give up’ a child. Consider how different those phrases sound, and how each might feel to sensitive ears.
    “‘Adoption triad members’ are anyone whose name might appear on a birth certificate: a child, birth parents, and adoptive parents.”

    We might recommend that you further familiarize yourself with adoption-related terms by reading the Wiki on “The Language of Adoption” (See https://en.wikipedia.org/wiki/Language_of_adoption)

    For legal adoption terms, check out https://family.findlaw.com/adoption/glossary-of-adoption-terms.html.

    Another good site (showing both positive and/or potentially outdated terms) is done by Friends in Adoption. (See https://www.friendsinadoption.org/adoption-resources/for-potential-adoptive-parents/resources-for-adoptive-families/adoption-terms/)

    As far as genealogists’ terminologies are concerned, it’s up to the individual genealogist which style of terms they ultimately opt to use. That said, we trust that you will be able to find and utilize the best terminology (in the aforementioned links) for yourself to better convey the spirit of those unique and wonderful relationships.

  4. This is a helpful article, but I notice that my specific question is not addressed, and the provided graphic left me still wondering: My “grand”mother’s sibling is my “great” uncle or aunt, but my sibling’s “grand”child is my “grand” niece or nephew.
    This strikes me as inconsistent, and I’m confused. If my grandmother’s sibling is my great, shouldn’t my sibling’s grandchild be my great also? Or vice-versa?
    I hope you have a consistent answer for me!

    1. Louise,

      Consistency is key for you to maintain your sanity as a genealogist, so brava for your aspirations for this quality of work!

      To answer your question, “great” and “grand” are oft interchangeable. Oxford Dictionary Online has the following entry for grand-aunt (See (https://en.oxforddictionaries.com/definition/grand-aunt):

      “Definition of grand-aunt in English:
      grand-aunt
      NOUN
      another term for great-aunt”

      This interchangeability often causes some confusion on the part of people as to what to call people–be it “great” or “grand”.

      That said, the Legal Genealogist says that the answer to your questions may be one and the same: Yes. (See https://www.legalgenealogist.com/2015/02/25/great-versus-grand/)

      You may read a whimsical answer here: https://www.grammarphobia.com/blog/2009/06/is-your-grandniece-great.html

      Ultimately, you’re right–consistency is key. If you opt to call someone “great” or “grand”, just make sure you define your terms beforehand. That way your consistency will help others’ heads stop spinning around the conundrum that is better known as the English language.

  5. My half-brother was legally adopted by my Mother’s sister. My Mother is his biological Mother. I’m not sure how I should connect him in my Tree. Any suggestions would be appreciated.

    1. Cheri,

      Most family tree (sites & software) nowadays have the option for you to be flexible (which is needed) when dealing with situations like this. You may label your half-sibling as having been legally adopted by your maternal aunt. She would then be listed as his adoptive mother while he’d show her as having adopted him. At the same time, your and his mother would still feature in his line as his birth mother.

      Another suggestion might be for you to look at blended family trees. Those usually show step-mothers/fathers, but the point is to get an idea of how trees might look when step-siblings are involved. You can always adjust templates to meet your family’s unique dynamics.

  6. In the modern age, I have found DNA cousins whom I happen to know exist because of a family member having participated in fertility clinics, etc. They probably will never know their true biological parent, as no adoption ever took place. Is there a way to handle this in a Family Tree?

  7. Al,

    That is a great question!

    I wish that I had a profound answer for how best to approach this, genealogically-speaking. I’m going to steer you to a site called DonorChildren.com. Their primary purpose is to assist in creating support, validation, and connection with anyone involved in the donor process. They have a wealth of resources (http://www.donorchildren.com/resources) that might be of assistance to you.

    I hope that this helps!

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