cousin? once removed?

Factual Questions
1

What’s the different between a “cousin” and a “cousin once removed”? Is it the difference between a blood relation and a relation through marriage? (no, not marrying a cousin :slight_smile: )

Also, I know “first cousins” are those that are the children of your aunts/uncles. But how are “second” and “third” etc. cousins determined?

2

A cousin-once-removed is the child of a cousin. A cousin-twice-removed is the grandchild of a cousin. The “removed” indicates a separation in generations.

A second cousin is the child of your mother’s or father’s cousin. Isn’t genealogy fun? Here’s a little diagram:
A
|
-------------
| |
B C
| |
-------- --------
| | | |
D E F G
| |
— —
| | | |
H I J K

B & C are siblings. D & G are first cousins (or just cousins). H & J are second cousins. Their kids would be third cousins.

Hope this all makes sense.

3

Damn, I forgot about the spacing thing.


                    A
                    |
               -------------
               |           |
               B           C
               |           |
            --------    --------
            |      |    |      |
            D      E    F      G
            |                  |
           ---                ---
           | |                | |
           H I                J K

That’s better.

4

“Once removed” refers to being in a different generation. Your mom’s sister’s daughter is your first cousin. You first cousin’s daughter is your first cousin once removed. I saw a good way of thinking about it in a thread here once. Let’s see if I can remember it. You identify the common relative, then count how many generations back that person is from each of the two cousins. Subtract one from the smaller of the two numbers and that’s the type of cousin. (1 = first cousin, 2 = second, etc.) The difference between the two numbers is number of times removed.

5

Forgot to add, in my diagram, D & J would be cousins once removed.

6

Easier way to remember:
First cousins: one of one’s parents is the sibling of one of the other’s parents.
Second cousins: one of one’s grandparents is the sibling of one of the other’s grandparents.
Third cousins: one of one’s great-grandparents is the sibling of one of the other’s great-grandparents.

7

Greg Charles has got it down best, and Jeff_B’s chart should help with the visuals. Only thing I need to add is that these relationships are not reciprocal. J is D’s first cousin once removed, but D is J’s parent’s cousin.

8

This link shows a handy little table that you can use to determine your relationship to a relative if you know your common ancestor. Judging from the data on his page, Dick Marston, the guy who put that page together, is my 7th cousin 3 times removed. He is also my 10th cousin twice removed, and probably related to me in many other ways as well.