half sister
noun
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half sister
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half-sister
half-sisternounthe daughter of either of one's parents by another partner
half sister
Americannoun
half sisters
plural
half-sister
British
noun
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
Etymology
Origin of half sister
Middle English word dating back to 1150–1200
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The girl, the half sister of Sarah's son, was born on Christmas Day 2022, and the family became a trio the following December.
From BBC ● Dec. 19, 2025
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
Death-Cast did not call Dalma Young because she isn’t dying today, but if they had, she would’ve spent the day with her half sister, and maybe even a Last Friend—she created the app, after all.
From "They Both Die at the End" by Adam Silvera
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
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
Only a month before, my ancient half-sister, who was twelve years older than me, had actually had appendicitis, and for several days before her operation I was able to observe her behaviour at close quarters.
From "Boy: Tales of a Childhood" by Roald Dahl
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
