Final answer:
Legend drugs are medications that must carry a cautionary statement indicating that federal law prohibits their dispensing without a prescription, ensuring they are used safely and under medical supervision.
Step-by-step explanation:
Drugs referred to as "legend" drugs are those that must carry the legend "Caution - federal law prohibits dispensing without a prescription." This designation is part of the regulations set by the Food and Drug Administration (FDA) to ensure that certain medications, which are usually prescription drugs, are distributed safely and appropriately. Legend drugs are typically potent substances that require medical supervision and thus cannot be sold over the counter without a prescription from a licensed healthcare provider.