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What is sister’s baby called?

This is a common question that many people have when a sister has a baby. The term used to describe a sister’s baby depends on your relationship to the sister. There are a few different terms that are commonly used.

Niece or Nephew

The most common terms used are niece or nephew. A niece is a sister’s daughter, and a nephew is a sister’s son. So if your sister has a baby girl, that baby is your niece. If your sister has a baby boy, that baby is your nephew.

For example, if your sister Jane has a daughter named Emma, then Emma is your niece. If Jane has a son named Noah, then Noah is your nephew. The terms niece and nephew refer to the child’s relationship to you – their aunt or uncle.

How Niece and Nephew are Used

The terms niece and nephew are used in a few different ways:

  • By blood relation – Your sister’s biological children are your nieces/nephews.
  • By marriage – If your sister-in-law has children, they are also considered your nieces/nephews.
  • Informally/honorary – Sometimes close family friends’ children are affectionately called nieces/nephews.

So niece and nephew broadly refer to a sister’s children, both biological and through marriage.

Reciprocal Terms

Niece and nephew are reciprocal terms. So just as your sister’s child is your niece/nephew, you are their aunt/uncle:

  • Your niece’s uncle = You
  • Your nephew’s aunt = You

This reciprocity reflects how the terms denote the relationship between you and your sister’s child.

Gender-Neutral Terms

If your sister has a baby but does not disclose the gender, there are a few gender-neutral terms you can use:

  • Nibling – A gender-neutral term combining niece and nephew
  • Sibkid – Meaning sibling’s child
  • Nephling – A blend of nephew/niece/sibling

You may also hear ‘pibling’ which is a gender-neutral term for parent’s sibling – so gender-neutral for aunt/uncle. The above terms are not as common as the traditional niece/nephew, but provide options if needed.

Cousin Terminology

Your sister’s baby and your child would be first cousins. Some key cousin terminology:

  • First cousins – Children of siblings (your sister’s child and your child)
  • Second cousins – Children of first cousins
  • Removed – Cousins separated by a generation are once removed, twice removed, etc.

So your sister’s baby is your child’s first cousin. Your sister’s grandchild and your child would be second cousins. Using ‘removed’ describes the generational gap.

Cousin Chart

Here is a chart showing some cousin relationships:

Relationship Example
First cousins Your child and sister’s child
Second cousins Your child and sister’s grandchild
First cousins once removed Your child and sister’s niece/nephew
Second cousins once removed Your grandchild and sister’s grandchild

This covers some of the basic cousin relationships to your sister’s baby. The ‘once removed’ highlights an age gap between the cousins.

Other Family Terms

Some other family terms used with a sister’s baby include:

  • Grandchild – Your sister’s baby is your parents’ grandchild, making them grandparents.
  • Sibling – Your sister’s other children would be the baby’s siblings.
  • Aunt/Uncle – The reciprocal terms for you as the baby’s aunt/uncle.

There are also extended family terms like great-aunt/uncle, referring to yourself in relation to your sister’s grandchild. Or grand-niece/nephew, referring to your sister’s baby in relation to your grandparents.

Family Tree

A family tree helps visualize some of these family connections:

Generation Relationship
Parents Grandparents to sister’s baby
You and Sister Aunt/Uncle to sister’s baby
Sister’s Baby Niece/Nephew to you
Your Children 1st Cousins to sister’s baby

This shows a few key relationships and how generations interact with the sister’s baby terminology.

Informal Babysitting Terms

If you will be babysitting your sister’s child, some cute informal terms include:

  • Auntie/Unc – Playful short forms of Aunt/Uncle
  • Cousin-Sitter – Highlights both your cousin and babysitting roles

You may also hear aunt-sitting or uncle-sitting to describe providing childcare for a niece/nephew. These playful terms underscore the close bond.

Babysitting Nicknames

Some other fun babysitting nicknames include:

Term Meaning
Auntie Nanny Mix of aunt and nanny
Cousin Care Cousin who provides care
Uncle Sitter Uncle who babysits

These creative nicknames highlight the special bond between an aunt/uncle and their niece/nephew.

In Other Languages

Different languages have their own family terms. Here are sister’s baby words in a few languages:

Language Sister’s Baby
Spanish Sobrino/Sobrina
French Neveu/Nièce
Italian Nipote
German Neffe/Nichte

So ‘sobrino/sobrina’ in Spanish or ‘neveu/nièce’ in French carry the same niece/nephew meaning. The terms have a similar feel across languages.

Cultural Variations

There can also be variations in family terms by culture. For example:

  • Mandarin Chinese has distinct terms for maternal vs. paternal sisters.
  • In Hebrew, niece/nephew equivalents vary if child of brother/sister.
  • Tagalog has gender-specific terms for nieces and nephews.

So the specifics around niece/nephew equivalents differ across cultures. But most languages have distinct familial terms like sister’s baby.


In summary, the most common terms for a sister’s baby are niece or nephew, depending on the gender. Niece refers to a sister’s daughter, while nephew is a sister’s son. Other familial terms like grandparents, cousins, and aunt/uncle are also used.

Some key takeaways:

  • Niece/nephew are reciprocal to your aunt/uncle status.
  • Gender-neutral options like nibling/nephling also exist.
  • Your child and sister’s child are first cousins.
  • Informal sitter terms highlight close bonds.
  • Languages have similar familial terms but some cultural variations.

So while niece and nephew are the most common terms, there are many creative ways to refer to the special relationship between an aunt/uncle and a sister’s baby. Whatever you call them, this new addition to the family is sure to bring joy and strengthen familial bonds.