No, you are correct. Your parents’ first cousins are your first cousins once removed. Your grandparents’ 1st cousins are your first cousins twice removed. Your great-grandparents’ 1st cousins are your 1st cousins thrice removed.
What Is a Second Cousin?
The number associated with your cousin has to do with how many generations away your common ancestor is. For example:
Sometimes you and your cousin may share a common ancestor, but you each call this ancestor something different. For example, the common ancestor may be your great-grandparent, but your cousin’s great-great grandparent.
This is where the phrase “once removed” comes in handy.
What Does it Mean to be a Cousin “Once Removed”?
To be a “once removed” from a cousin means you are separated by 1 or more generations.
If you look at the cousin chart above (Post #14), you’ll see that each row is color-coded by generation. You, your siblings, and your first, second, and third cousins are all of the same generation.
You may have noticed that the boxes labeled “cousin once removed” are either from one generation above or below you. You are “once removed” if you are separated by 1 generation and “twice removed” if you are separated by 2 generations, and so on.
Quick Tip: Your parent’s first, second, and third cousins are also your first, second, and third cousins—but once removed. This is because your parents and their generation are 1 above yours. Likewise, your grandparents’ first, second, and third cousins are also your first, second, and third cousins, this time twice removed. This pattern continues throughout each generation. So, for example, a first cousin once removed is either the child of your first cousin or the parent of your second cousin.