It may seem simple enough to keep track of the people in your family tree when you are just starting out, and you only have a few generations of direct relationships to handle. But once that tree gains a few more branches, you can quickly lose track of how people are related to you.
When looking back through your ancestors, it is pretty easy. The convention is that your parent’s parents are your grand-parents, and then each generation after that has the addition of “great” to the front. So when you move back through your family tree, each generation gains an extra “great”. Your great-grandparents are 3 generations away from you, and your great-great-great grandparents would be 5 generations from you. Though it can be hard to keep track of all the “greats”, it makes for an easy system of understanding where a relative sits in your family tree.
The real difficulties lie in those other branches that lead away from your direct ancestors. In other words, most of the complexity comes from cousins. When we hear about 3rd cousins, twice removed we can start to get a little anxious because it’s not so easy to place such a person on your family tree.
To understand the terminology, you need to consider both parts of the phrase. “3rd cousins” means one thing, and “twice removed” means another. When you and another person are 3rd cousins, this means that the ancestor you have in common is 3 generations back in your family tree, which would be your great-grandparents. If you shared your grandparents, then you would be 2nd cousins. Large family trees can lead to very distant relations where you can find yourself with 20th cousins if you are lucky.
The “twice removed” part tells you how many generations that your cousin is away from you. If they are roughly the same age as you and part of the same generation, then there is no “removed” used. If the other person is one generation away from you, such as your parent’s or children’s generation, then they are “once removed”.
You probably won’t be able to work your way through your genealogy information right off the bat and mentally identify everyone as you go. But with a little patience, you can master the art of identifying your distant relatives in a way that helps keep you aware of what their relation to you is.
Even simpler, use a software program that figures all of it out for you. Of course, you still need to know what the terminology means when the program tells you that a person is your 4th cousin, once removed.
It’s not crucial that you understand these family tree terms, but it can really help when you have a large number of people to keep organized. It also helps if you are discussing your genealogy work with a relative, and you need to help them orient where they are in your research.