Definition of prescribe verb from the Oxford Advanced Learner's Dictionary. (of a doctor) to tell somebody to take a particular medicine or have a particular treatment; to write a prescription for a particular medicine, etc. prescribe something Valium is usually prescribed to treat anxiety. established or decided beyond dispute or doubt adjective conforming to set usage, procedure, or discipline “in prescribed order” synonyms: official regular in accordance with fixed order or procedure or principle The product will have to meet internationally prescribed (= demanded) standards. 2 meanings: 1. recommended by a doctor 2. laid down or recommended formally. Click for more definitions. The meaning of PRESCRIBE is to lay down a rule : dictate. How to use prescribe in a sentence. PRESCRIBED definition: dictated or indicated as a rule or course of action to be followed. See examples of prescribed used in a sentence. 1. To set down as a rule, law, or direction: prescribed the terms of the surrender. 2. To order the use of (a medicine or other treatment).