Cousinship

If two persons share a common pair of parents, they are brothers, sisters or brother and sister. Cousins, on the other hand, share a common pair of grandparents. These are elementary relationships that we are familiar with and that are pretty straight forward. 

 

But have you come across mention of first/second/third cousins, once/twice removed?

 

I have often read of such relationships and I am intrigued by them. After much procrastination, today I finally decided that it is time to end my ignorance. 

Here are my findings. 

Cousin (a.k.a "first cousin")

Your first cousins are the people in your family who have two of the same grandparents as you. In other words, they are the children of your aunts and uncles.

Second Cousin

Your second cousins are the people in your family who have the same great-grandparents as you, but not the same grandparents.

Third, Fourth, and Fifth Cousins

Your third cousins have the same great-great-grandparents, fourth cousins have the same great-great-great-grandparents, and so on.

Removed

When the word "removed" is used to describe a relationship, it indicates that the two people are from different generations. You and your first cousins are in the same generation (two generations younger than your grandparents), so the word "removed" is not used to describe your relationship.

The words "once removed" mean that there is a difference of one generation. For example, your mother's first cousin is your first cousin, once removed. This is because your mother's first cousin is one generation younger than your grandparents and you are two generations younger than your grandparents. This one-generation difference equals "once removed."

Twice removed means that there is a two-generation difference. You are two generations younger than a first cousin of your grandmother, so you and your grandmother's first cousin are first cousins, twice removed.

Relationship Charts Simplify Everything

Now that you have an idea of what these different words mean, take a look at the chart below. It's called a relationship chart, and it can help you figure out how different people in your family are related. It's much simpler than it looks, just follow the instructions.

Instructions for Using a Relationship Chart

1. Pick two people in your family and figure out which ancestor they have in common. For example, if you chose yourself and a cousin, you would have a grandparent in common.
2. Look at the top row of the chart and find the first person's relationship to the common ancestor.
3. Look at the far left column of the chart and find the second person's relationship to the common ancestor.
4. Determine where the row and column containing those two relationships meet.

Common Ancestor	Child	Grandchild	G-grandchild	G-g-grandchild
Child	Sister or Brother	Nephew or Niece	Grand-nephew or niece	G-grand-nephew or niece
Grandchild	Nephew or Niece	First cousin	First cousin, once removed	First cousin, twice removed
G-grandchild	Grand-nephew or niece	First cousin, once removed	Second cousin	Second cousin, once removed
G-g-grandchild	G-grand-nephew or niece	First cousin, twice removed	Second cousin, once removed	Third cousin

Source: http://www.genealogy.com/16_cousn.html

If you want to be more precise...

First cousins can be classified two ways: patrilateral or matrilateral, and cross- or ortho-cousins. While ortho-cousins are children of two brothers or two sisters; cross-cousins are children of a sister and brother. Someone is your patrilateral cousin if you are first cousins through your father (and your father’s brother or sister); someone is your matrilateral cousin if you are first cousins through your mother (and your mother’s brother or sister).

Source: http://oakroadsystems.com/genl/relation.htm

And now for some application: 

• My daughter and the children of my husband's brother are patrilineal ortho-cousins.
• My daughter and my sister's children are matrilineal ortho-cousins. 
• My daughter doesn't have any cross-cousins on either side of the family because her dad's sister does not have any children and my brother is not married.
• The relationship between my daughter and my first cousins is first cousin, once removed.

In accordance with Chinese family hierachy my daughter still addresses her first cousins, once removed as uncle or aunt. Socially it sounds strange to introduce someone of your own age or younger as your uncle or aunt. Introducing them as your cousin saves you a lot of explanation but the traditionalists will be horrified. It's a no-win situation.