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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

When she opened her results and saw the mind-boggling truth that her twin was her half sister, Lavinia was distraught - and furious.

From BBC ● May 2, 2026

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

From The Wall Street Journal ● Dec. 4, 2025

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

Paparazzi spotted Corinne, her half sister Anelise and Anelise’s mom, Kristin Grannis, at the facility in May.

From Los Angeles Times ● Jul. 10, 2023

Barack’s half sister Maya and her husband, Konrad, came with us, along with their daughter Suhaila, a cute little four-year-old.

From "Becoming" by Michelle Obama

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

“He’s very sick and very mentally ill,” his half-sister said, noting that he suffered from schizophrenia but refused to take his medication.

From Los Angeles Times ● Jul. 24, 2026

The couple lived in the block of flats with the boy's siblings - his 12-year-old sister and 10-year-old half-sister.

From BBC ● Apr. 10, 2026

The baby’s half-sister would be easier for the older couple to take care of.

From Salon ● Mar. 24, 2026

It’s funny how I seemed to think of Maiy as Ella’s sister, instead of her being, just as Ella is, my own half-sister.

From "The Autobiography of Malcolm X" by Alex Malcolm X;Hailey