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half brother
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half-brother
half-brothernounthe son of either of one's parents by another partner
half brother
Americannoun
noun
Usage
What does half brother mean? A half brother is a brother who is related to his 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 son with another partner (who is not the person’s parent), the son is considered the person’s half brother. The term half sister is used in the same way. Half-sibling is a gender-neutral way of saying the same thing. In contrast, the words stepbrother, stepsister, 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 brother and its related terms only refers to the biological relationship. Half brothers may have close relationships with their siblings, and many people simply call their half brother their brother. 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 brother and my paternal half sister and we had a great time.
Etymology
Origin of half brother
Middle English word dating back to 1300–50
Compare meaning
How does half-brother compare to similar and commonly confused words? Explore the most common comparisons:
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:
But upon her father’s death, her younger half brother Aegon — who was born after Rhaenyra was named heir — was crowned king of the Seven Kingdoms instead.
From Los Angeles Times ● Jun. 17, 2026
A brother and sister in Utah were fighting over their late father John Heater’s estate when the brother reached out to a man he thought might be their half brother.
From The Wall Street Journal ● Nov. 30, 2025
She was saved by her half brother Billy after he smelled smoke.
From Salon ● Dec. 27, 2023
“They said it might take days to clear up,” said the half brother, Cristopher Miranda.
From New York Times ● Oct. 2, 2023
In the hole from its root ball archaeologists discovered a set of steps carved with the biography of B’ajlaj Chan K’awiil, a younger brother or half brother to Mutal’s dynasty-restoring king, Nuun Ujol Chaak.
From "1491" by Charles C. Mann
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But that setup changed two years ago when Ratan died and his half-brother Noel took over Tata Trusts.
From The Wall Street Journal ● Aug. 20, 2026
It was probably commissioned by Bishop Odo of Bayeux -- William the Conqueror's half-brother -- in 1077 to decorate the new cathedral in his hometown, Bayeux, according to the tapestry's home museum.
From Barron's ● Jul. 10, 2026
Jerome Boateng of Germany faced older half-brother Kevin Prince of Ghana in Johannesburg in 2010.
From BBC ● Jun. 20, 2026
King Aegon II is Rhaenyra’s younger half-brother who was born after she had already been announced as Viserys’ heir.
From Los Angeles Times ● Jun. 19, 2026
Black Donnel Flint and his half-brother Artos only lost one man between them.
From "A Dance with Dragons" by George R. R. Martin
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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.