What does 9th cousin once removed mean?

If you’re like many people, you may have heard the phrase “9th cousin once removed” and wondered what it all means. It sounds complicated but, in reality, it is a simple concept that just requires some understanding of how family relationships play out over time. Read on to learn more about what this term means and why it is used in genealogy research.

The Basics of Family Relationships

Before delving into exactly what 9th cousin once removed means, let’s first take a look at the basics of family relationships. Most people are familiar with basic terms such as mom, dad, sister, brother, and so on. But when it comes to extended family members, things can get a bit more complicated. That’s because we use specific terms to describe our relationship with them—terms like aunt and uncle or first cousin. So what exactly do those terms mean?

An aunt (or uncle) is the sibling of one of your parents; first cousins are the children of your parents’ siblings; second cousins are the children of your parents’ first cousins; third cousins are the children of your parents’ second cousins; and so on. As you can see, these relationships become increasingly distant with each generation.

What Does “9th Cousin Once Removed” Mean?

Now that we’ve established some basic family relationships, let’s talk about what 9th cousin once removed means. To understand this term, you need to understand two concepts: degree and removal. Degree refers to how distant two people are from each other in terms of generations—in this case, nine generations apart—and removal refers to whether they are from the same generation (no removal) or different generations (once removed).

Therefore, 9th cousin once removed describes two people who are nine generations apart and from different generations—for example, if one person is your great-great-great-grandparent’s grandchild and the other is their great-great-great-grandparent’s grandchild (nine generations).


Understanding family relationships can be tricky but having an understanding of key terms like 9th cousin once removed can help make things easier. Knowing how to correctly use these terms will also help you better understand family trees and genealogy research in general. Whether you’re new to genealogy research or a seasoned pro looking for a refresher course on terminology, this article should provide some valuable insight into how far back our families go!


1. What is 9th cousin once removed?

9th cousin once removed is a term used to describe two people who are nine generations apart and from different generations, such as if one person is the great-great-great-grandchild of your great-great-great-grandparent and the other is their great-great-great-grandchild.

2. Why is 9th cousin once removed used in genealogy research?

9th cousin once removed is often used in genealogy research because it helps to understand family relationships over time, as well as how they are connected to one another. Understanding this concept can help you to better understand family trees, genealogy research, and the history of your family.

3. How do I determine my relationship with a 9th cousin once removed?

There are several different methods that can be used to determine your relationship with a 9th cousin once removed. Some common approaches include counting generations, using a family tree, and doing genealogical research. It is important to note that there is no one “right” way to do this, as different people will use different methods and come up with slightly different answers.

4. Is 9th cousin once removed something I need to be concerned about when doing genealogy research?

While 9th cousin once removed may be a somewhat complicated concept, it is important when doing genealogy research because it can help you to better understand your family tree and the connections between different members. This can be helpful both in terms of gaining insight into your family history, as well as if you are trying to break down any myths or rumors that may be circulating in your family. In the end, it is up to you to decide whether or not to focus on 9th cousin once removed and other related concepts when doing your genealogy research.

5. Can I find out more information about my relationship with a 9th cousin once removed?

Yes, there are many resources available to help you learn more about your 9th cousin once removed and other family relationships. Some good places to start include online genealogy tools, family history websites and books, and local libraries or historical archives. No matter what approach you take, understanding these concepts is an important part of doing effective genealogy research.​