0 a man who has promised to treat another man as his brother in a ceremony in which they cut themselves and mix their blood together
I had warmed to his battered old hat at sight of it, and he was as solicitous for my welfare as if we were blood brothers.
They will do him no harm if he is willing to be their "blood brother."
In another case a life-insurance policy was taken out for the benefit of a 'blood brother'.
Nothing we could do could persuade them to leave the hook, which they had learned to live with as their blood brother, because it was letting their own blood.
He saved the sultan's daughter from an unwanted marriage after she entreated him, as her blood brother, to help her.
This is similar, in many ways, to becoming a blood brother.
We are in the most literal sense blood brothers and blood sisters.
