blood brother

American  

noun

1. a person's brother by birth.

2. a male person bound to another by ties of great friendship.

3. something usually associated with or thought to exist inseparably from another thing, quality, circumstance, etc..

   Humility is often the blood brother of patience.

4. a male established in a close relationship with another male through the performance of a specific ritual, as the commingling of blood.

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blood brother British  

noun

1. a brother by birth

2. a man or boy who has sworn to treat another as his brother, often in a ceremony in which their blood is mingled

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Other Word Forms

• blood brotherhood
  noun

Etymology

Origin of blood brother

Middle English word dating back to 1350–1400

Example Sentences

See Examples For:

blood brother

Mkhwanazi, who has since been suspended, denied the allegations but did admit to receiving money from Matlala, describing him as a "blood brother" during his appearance at the Madlanga Commission.

From BBC ● Jul. 14, 2026

Riding shotgun was Sumlin’s military blood brother, Sgt. 1st Class Jason Jarvis, a soldier on active-duty from Fort Bragg’s 18th Ordnance Company in North Carolina — Sumlin’s old unit.

From Seattle Times ● Dec. 15, 2021

It’s also an origin story for Tomisaburo, or Storm Shadow — the prominent hero/villain and blood brother to Snake Eyes.

From Los Angeles Times ● Jul. 22, 2021

It opens with the lines: “My blood brother is an immigrant / A beautiful immigrant.”

From The Guardian ● Oct. 14, 2020

Most of the stories we have, however, concern two gods, Odin and his son Thor, and Odin’s blood brother, a giant’s son called Loki, who lives with the Aesir in Asgard.

From "Norse Mythology" by Neil Gaiman