To stop the flow of something, especially blood.
Stanching blood is important for helping someone who is hurt.
Examples:
He stanches the blood with a bandage.
The doctor stanches the bleeding with a pressure bandage.
She stanches the wound to help her friend.
The nurse stanches the blood flow with a tight bandage.
He stanches the bleeding quickly to help the hurt person.
The first aid kit helps stanch the blood when someone is hurt.