Final answer:
The abbreviation 'sig' stands for 'label as follows' in medical prescriptions, instructing patients on how to take their medication. 'NPO' refers to 'nothing by mouth', and 'OTC' means over-the-counter medication.
Step-by-step explanation:
The abbreviation that means label as follows is sig. In medical prescriptions, sig is derived from the Latin term 'signetur', which instructs the patient on how to take the medication prescribed by the doctor. This can include instructions on dosage, frequency, and method of administration. Some examples of sig might include 'take one tablet by mouth twice daily' or 'apply topically to the affected area once daily'.
The other abbreviations provided have different meanings in the medical context. NPO, stands for "nil per os" or "nothing by mouth," which is used to instruct patients not to take anything orally, often before surgery or certain medical tests. OTC stands for over-the-counter, which refers to medications that can be purchased without a prescription. TOP is not commonly used as an abbreviation in medical prescriptions.