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• half sister
  half sister

  noun

  sister.
• half-sister
  half-sister

  noun

  the daughter of either of one's parents by another partner

half sister

American  

noun

• half sisters
  plural

1. sister.

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half-sister British  

noun

1. the daughter of either of one's parents by another partner

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Usage

What does half sister mean? A half sister is a sister who is related to her sibling(s) through only one parent. This typically means that they share only one biological parent (not both). For example, when a person’s parent has a daughter with another partner (who is not the person’s parent), the daughter is considered the person’s half sister. The term half brother is used in the same way. Half-sibling is a gender-neutral way of saying the same thing. In contrast, the words stepsister, stepbrother, and stepsibling refer to those who have a sibling relationship (often based on the remarriage of their parents to other partners) but who do not share a biological parent. The word half in half sister and its related terms only refers to the biological relationship. Half sisters may have close relationships with their siblings, and many people simply call their half sister their sister. Modifiers such as maternal and paternal are sometimes used to specify which biological parent the siblings have in common. Example: Over the holidays, I got together with my maternal half sister and my paternal half brother and we had a great time.

Other Word Forms

Noun Inflected Forms

• half sisters
  plural

Etymology

Origin of half sister

Middle English word dating back to 1150–1200

Example Sentences

See Examples For:

half sister half-sister

Ms. Kuehn met her father’s half sister, Ruth, only once, in 1987.

From The Wall Street Journal ● Dec. 4, 2025

A federal judge on Tuesday dismissed a defamation lawsuit against Meghan, Duchess of Sussex, after her half sister accused her of spreading “disparaging, hurtful and false” statements in interviews.

From New York Times ● Mar. 12, 2024

Emily's half sister, Natali Hand, has issued an appeal to the Irish government to help "get her back".

From BBC ● Nov. 6, 2023

Breasia was the half sister of Dinkins’ son, and investigators have said both children were staying the night with him at the apartment where he was living with a girlfriend.

From Seattle Times ● Aug. 10, 2023

I skipped over my half sister and asked, “What did my mother want to know about me?”

From "Three Little Words: A Memoir" by Ashley Rhodes-Courter

The irony is that Sally was also Martha’s half-sister — the product of John Wayles’ relations with an enslaved woman — making her biological kin to the Monticello Association members, too.

From Salon ● Jul. 27, 2026

Last year, he checked into a psychiatric facility, his half-sister said, and seemed to be doing well.

From Los Angeles Times ● Jul. 24, 2026

Barker was also able to dig into his father's background, learning he had three half-brothers and a half-sister.

From BBC ● Jun. 23, 2026

Although he kept contact with his father while in care, his coordinator helped him establish relationships with his wider family, including aunts, uncles, cousins and a half-sister.

From BBC ● Jun. 4, 2026

She might be my half-sister, but she looks wholly happy to see me.

From "X: A Novel" by Ilyasah Shabazz