Euthanasia
Some people say that doctors may treat a person to reduce their pain, and as a result the person will die sooner. If the doctor gives the treatment in order to help the patient die, then it is euthanasia. But if the doctor gives the treatment in order to stop the pain, and does not intend for the patient to die, then it may not be euthanasia, even if the doctor knew that the treatment would kill the patient.