[n] a drug that is available only with written instructions from a doctor or dentist to a pharmacist; "he told the doctor that he had been taking his prescription regularly"
[n] written instructions from a physician or dentist to a druggist concerning the form and dosage of a drug to be issued to a given patient
[n] written instructions for an optician on the lenses for a given person
[n] directions prescribed beforehand; the action of prescribing authoritative rules or directions; "I tried to follow her prescription for success"