Final answer:
The abbreviation a physician would write to discontinue a medication or treatment is 'DC' or 'D/C'. It is important in healthcare settings to ensure correct adherence to treatment plans.
Step-by-step explanation:
When a physician decides to discontinue a treatment or medication, they may write DC or D/C on a medical order. This abbreviation is a directive to cease the administration of the medication or to stop the ongoing treatment. It's important that this instruction is followed accurately in the healthcare setting to ensure patient safety and adherence to the physician's treatment plan.