The term RX Specification refers to a job description that involves two components: TER (3 letters) and DOSE (4 letters). TER stands for 'Therapeutic Effectiveness Rating' and is a measure of how effective a drug is in treating a particular condition. DOSE stands for 'Dosage Strength' and is the amount of a drug that is prescribed to a patient. RX Specification is a combination of these two components, which are used to determine the best course of treatment for a patient.