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• half brother
  half brother

  noun

  brother.
• half-brother
  half-brother

  noun

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

half brother

American  

noun

1. brother.

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half-brother British  

noun

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

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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:

• half brother vs. stepbrother

Example Sentences

See Examples For:

half brother half-brother

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

Her vehicle was built by Walt Arfons, who was in the thick of competing against his half brother, Art, and Breedlove.

From Seattle Times ● Dec. 26, 2023

He missed the girls too, even Sansa, who never called him anything but "my half brother" since she was old enough to understand what l>astard meant.

From "A Game of Thrones" by George R.R. Martin

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

While he also briefly studied overseas in Switzerland, he was said to be a lot more insulated than his half-brother Kim Jong Nam.

From BBC ● Jun. 27, 2026

The remaining members of EW&F, including original members Philip Bailey, White’s half-brother Verdine, and Ralph Johnson, form one of the few nostalgia acts that can still draw people to arenas.

From Salon ● Jun. 7, 2026

Ferrer later learns of another half-brother, her father’s son; these fraught relationships are the pillars of a gorgeous meditation on belonging.

From Los Angeles Times ● May 1, 2026

My mother took one pair of oars and my fairly ancient half-brother took the other, and off we would go.

From "Boy: Tales of a Childhood" by Roald Dahl