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.

---

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

---

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

“Gangsta Boo was like a sister to me and told the world about me the way my blood brother did,” Drumma Boy said in a statement.

From Seattle Times ● Jan. 2, 2023

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

He feels he must go to save Bon, his blood brother, from dying in what he’s sure will be a suicide mission.

From New York Times ● Apr. 2, 2015

Then I went to my capten and asked him if I cood talk to a reb prisner that was my own blood brother.

From "Across Five Aprils" by Irene Hunt