Here’s a guide to help you find the right term for all the complicated familial ties.

By Lucy Wendel
Updated August 05, 2019

With all the steps and seconds and greats and grands, it's no surprise that we feel like we need a map to figure out who our relatives are to us. (And if you have an especially big crew or a blended family, things can get seem even more complicated.) Although the different terms can be a bit confusing, there's no need to involve a complicated trigonometric algorithm to identify your cousin's actual ties to your family. We enlisted help from Crista Cowan, corporate genealogist for Ancestry, to help us understand what all the different labels mean.

We broke down each term and explained what they each mean, using "you" as the frame of reference around which all other relations revolve. With this chart, you'll be a whiz by the time your next family reunion rolls around. Plus, there's a printable version for you to download below, so everyone can understand what it means to be a first cousin once removed.

Credit: Kevin R. Morris/Getty Images

Nuclear Family

This is your primary family group: your mother, father, brothers, sisters, your spouse, and your children. The term usually refers to the parents (or parent) plus their dependents, which can also include step-parents, step-siblings, and adopted children. This term was first used in the early 20th century to refer to a financially viable social unit and can be used in contrast with extended family (which includes aunts, uncles, cousins, and grandparents).

Uncle and Aunt

These are the siblings (brothers and sisters) of your parents. It also includes their spouses. You don't need any blood connection to be a full-fledged aunt or uncle. Your mother's sister's husband is not your "uncle-in-law" just because he isn't related to you by blood. He's only your uncle, fair and square.

Niece and Nephew

The son and daughter of your sibling. As with uncle and aunt, these people are not considered your "niece by marriage" or "nephew-in-law," even though they might be your spouse's siblings kids and not related to you by blood. They are simply your niece and nephew.

The exception to the terms "aunt/uncle" and "niece/nephew" would be when DNA is being considered. If you are not related by blood to that relative (that is if your familial connection is through a spouse), you will not share DNA and therefore, might be considered in different terms, depending on the situation.

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Your cousin (also known as first cousin, full cousin, or cousin-german) is the child of your parent's sibling. You and your first cousins share one set of grandparents. (A "cousin-german," by the way, comes from "cousin Germain," which is French for first cousin.)

Double First Cousins

Although rare in present-day, double first cousins necessitate a seat at the family diagram table, too. When a set of siblings from one family marries a set of siblings from another family, their kids are not only first cousins; they're also double first cousins. These lucky kids have both sets of grandparents in common. Double first cousins were more common in bygone eras when families lived in smaller towns and rural areas over many generations.

Second Cousins

You and the child of your parent's cousin are second cousins. The two of you share at least one set of great-grandparents in common. Think of them as first cousins, because they are in the same generation as you, but with an added generation between yourselves and your linking ancestor. Similarly, your child and your cousin's child are second cousins to each other.

Third Cousins

Following the same equation as second cousins, third cousins are cousins with two added generations between yourselves and your linking ancestors. You and the children of your parent's second cousin are third cousins, and you share at least one set of great-great-grandparents in common.

The same equation can continue for fourth cousins, fifth cousins, and so on.

First Cousin Once Removed

If your first cousin has a child, that child is your first cousin once removed. "Removed" refers to a difference in generation from you and your first cousin. You can also think of it relative to that shared set of ancestors that you share with your first cousin, which would be your grandparents.

"Removed simply means they're not in the same generation," Cowan says. If that cousin once removed has a child, then that child is your first cousin twice removed, because they are two generations removed from you and your first cousin.

This "removed" business is often confused with labeling a relative a "second" or "third" cousin, which is inaccurate. "A cousin of any degree will always be in the same generation as you," Cowan explains. "As soon as you start adding generations, like children or grandchildren of a cousin, that's when we get to once removed, twice removed, and so on." If you're still confused, you can watch this video from Ancestry for a visual explanation.

Grandaunt and Granduncle

If you call your grandpa's sister, your "great-aunt," you are not alone. But technically, this terminology is incorrect, according to experts. "Grand" refers to the generation above your parents (as in "grandparents"), though "great" implies an added generation beyond that. (Your "great-grandparents" are your grandparents' parents.) So really, your grandpa's sister should be called your "grandaunt." But don't worry, we won't fault you if you keep referring to her by the more commonly used "great-aunt," and she probably won't either.

Great-Grandaunts and Great-Granduncles

These are the siblings of your great-grandparents. The parents of your great-grandaunt are your great-great-grandparents.


This is your family by marriage: your spouse's parents, spouses of your siblings, and spouses of your spouse's siblings. In-laws pretty much stop with your parents-in-law and your siblings-in-law. That is, your brother's wife is an in-law, but none of her siblings are. And your husband's sister's husband is your in-law, but none of his brothers are. You are not in-laws with the parents of your sister-in-law's husband. And the two sets of parents of a couple are not in-laws to each other, either. They are considered competitive parents or co-in-laws.

Affinity Relatives

Similar to your in-laws, your affinity relatives are your spouse's blood relatives. This can include your spouse's parents, siblings, aunts, uncles, cousins, and grandparents.

Birth Mother, Biological Mother, Natural Mother

These are terms for the biological mother of a child who has (usually) been adopted by other parents.

Collateral Relatives

These are any relatives related to you by blood but who are not a direct ancestor. So if your immediate ancestors are your parents, grandparents, great-grandparents, and so on, your collateral relatives are your cousins, aunts, uncles, and siblings.

Birth Parent, Biological Parents, Natural Parent

These are all terms for the parent whose DNA you have. These are often used to explain the biology of a child who is adopted, or when one parent is absent.

Adoptive Parent

This refers to a parent or set of parents who have adopted a child. Biologically, the child is not their own. It's possible to be biologically related if the adoptive parent is an aunt, uncle, cousin, or some other blood relative.

Step Relationship

A "step" connection is the result of a marriage that did not result in a blood relation to you. For example, if your father marries a woman who is not your mother, she is your step-mother. Her daughter, who is not related to you by blood, is your step-sister. Within your family tree, these relatives take on the position that any biological relative would, but without a blood relation.

This type of relationship can be applied to any family connection: step-parent, step-sibling, step-uncle, step-grandmother, and so on.

Half Relationship

When you and a sibling share one parent in common but not both, that person is your half-sibling. Similarly, your mother's half-sister is your half-aunt. Your half-sister's daughter is your half-niece. A half-cousin means that their parent is the half-sibling of your parent.


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