Family can be complicated. Not just the people themselves, but the connections that bind them together. Marriage, divorce, birth and death can all tangle up the branches of our family trees, and even the most seasoned English speaker might struggle to tell you what a third cousin twice removed really means. With that in mind, we put together this guide to talking about family, with a close look at some of the more difficult terms.

The Family Tree Terminology: Family Vocabulary In English

English Family Terms

• family tree
• relatives
• grandmother (grandma)
• grandfather (grandpa)
• parents
• mother (mum)
• father (dad)
• siblings
• sister
• brother
• children
• daughter
• son
• niece
• nephew
• grandchildren (one grandchild)
• granddaughter
• grandson

How To Describe Family In English

For the more difficult web of connections, here’s a brief guide.

In-Laws Vocabulary

An in-law is someone you’re related to by marriage (thus, legally related to). Your mother- and father-in-law are the parents of your spouse, and your brothers- and sisters-in-law are your spouse’s siblings.

A Half-Sibling Explanation

One of the easier ones to figure out: a half-brother or half-sister is someone you share one, but not two, parents with.

Step-Siblings In English (And Other Step-Relations)

A step-sibling or step-parent is also related to you through marriage — but your parents’, not your own. Your step-father or step-mother, for example, is someone who married your biological mother or father. A step-sibling is the child of your step-father or step-mother. You can widen the circle more to include step-aunts and step-uncles, but then it does get more complicated. For example, a step-niece or -nephew can be the child of your step-sibling, or the stepchild of your sibling. There is no English term for the stepchild of a step-sibling, so once you get past that level of complexity, everyone gets the word “step.” 

Cousin Definitions In English

Cousins are perhaps the most confusing, so let’s break that down. One way to think about it is that first, second and third cousins are defined by which generation of great grandparents you have in common. If someone has two of the same grandparents, that’s a first cousin. If you have two great grandparents in common, that’s a second cousin. If it’s great great grandparents, it’s a third cousin, and so on. Put another way:

• First Cousin — the child of an aunt and uncle.
• Second Cousin — the grandchild of a grand-aunt and grand-uncle (one of whom is a sibling of a grandparent).
• Third Cousin — great grandchild of a great grand-aunt and great grand-uncle.

Alright so that’s one kind of separation, but then there’s once, twice and thrice removed. The easiest way to think about that is that it has to do with generations. Any cousin who is not removed at all is not removed at all. Your first cousin’s children are your first cousins once removed, your first cousin’s grandchildren are first cousins twice removed, and so on. The same goes for second cousins (their children are second cousins once removed, etc.).

Where things get even more confusing is that the “removed” label also refers to older generations. Your second cousin’s parents are your first cousins once removed. Then, your third cousin’s parents are second cousins once removed, and their grandparents are first cousins twice removed. At this point, though, you might as well just go with “cousin” and keep things simple.