Siblings and in-laws: talking about family relationships

young woman taking selfie with family
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by Liz Walter

Family is important to most cultures at this time of year, so this post looks at the way we describe family relationships. I’m going to assume that you already know the basic family words such as aunt, grandmother, cousin and nephew and concentrate on some more interesting terms.

Let’s start with the general words relatives and relations. These words both mean all the people in your family. We often use them particularly for family members we don’t live with:

We are going to visit some relatives this weekend.

Be aware that the word parents is a false friend for speakers of some languages: in English, it means your mother and father, not other relations.

The generations of your family are the people of a similar age. So you and your brothers and sisters are one generation, your parents, aunts and uncles the generation above, and your grandparents the generation above that.

A more formal word for either a brother or sister is sibling. Two babies born to the same mother at the same time are twins. If they develop from the same egg and look alike, they are identical. If not, they are non-identical.

There are several common affixes associated with family relationships. A half-brother/sister has one of the same parents as you. Step- is used to describe relationships that come from a second or later marriage, so for instance, someone’s stepmother is their father’s wife and they are that woman’s stepson or stepdaughter.

The suffix -in-law is used for relationships by marriage. Your father-in-law is your wife or husband’s father, and your sister-in-law is your wife or husband’s sister. In-laws is also used as a noun to mean your wife or husband’s family, especially their parents:

My in-laws live in America.

Your ancestors are people from your family who lived in earlier times. You and your family are their descendants. Your blood relations/relatives are people who have one or more shared ancestor. In other words, you are related by birth, but you may be related to other people by marriage.

If you are directly related to someone, you share a close relative, for instance a parent or grandparent. If the relationship is less close, you might say you are distantly related. Similarly, your immediate family consists of close relations such as siblings, parents and children, while your extended family includes aunts, uncles, cousins, etc.

We use the slightly formal words maternal and paternal to describe which parent someone is related to, for instance a maternal aunt or paternal grandparents. More informally, we say that a relative is from our mother or father’s side of the family.

Finally, something that confuses many English speakers: a first cousin is the child of your aunt or uncle and a second cousin is the child of one of your parents’ cousins. The phrase once removed means ‘one generation different’. So, for instance your father’s cousin is your first cousin, once removed.

16 thoughts on “Siblings and in-laws: talking about family relationships

  1. Yuti

    Your co-sister is your husband’s brother’s wife, your co-brother is your wife’s sister’s husband. I’m not sure how common the usage of these terms is now — sister-in-law / brother-in-law seem to have taken over.

    1. Liz Walter

      Hi Yuti. I’ve never heard of co-sister/brother – it’s certainly not used currently in British English, though maybe it is used in a different variety of English.

  2. Grace

    My question, please:
    The lady is my father’s cousin. I am her first cousin, once removed, in other words, I’m her second cousin.
    Is it correct?
    Thank you for your time,

    1. Liz Walter

      Oh dear, these relationships are so complicated, and to be honest, very few people understand the rules. So, you are correct that you are her first cousin once removed, but as I understand it, her children (not the lady) would be your second cousins.

  3. Ivy

    Are the first cousin and the second cousin the same generation? Besides, can I just simply call my parent’s cousin aunt or uncle?


    Dear Liz!
    I am glad to recieve new curriculum topics of Yours again.
    Today is the 25-th of December and i’m reallly rejoicing to congratulate You on Holiday, tu bring my best wishes to You.
    Merry Christmas to You!

  5. Gene Durward Johnson

    In my mother’s side of the family, my first cousins become aunts and uncles to my children as do I to their children. That pattern follows out with all with the children. So my kids and their kids are cousins and they become aunts and uncles to their children basically as a matter of respect due to their ages. We don’t follow the 1st , 2nd and 3rd cousin regimen. After awhile everyone just call each other cousins if they are near in age and if the other person if older they become and aunt or uncle even though they maybe a 3rd cousin. Our family re union are huge .

  6. Zz's Mom

    …so where does the phase “step-” come from, and what do you call them once the parent gets divorced? Aren’t step sisters/brothers technically “in-laws” also? I am very ‘grown’ with my own family/children and my father just got married. All ‘those people’ are in-laws to me.

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