Which abbreviation refers to the rectal route of medication administration?

The abbreviation that refers to the rectal route of medication administration is "pr," which stands for "per rectum." This term indicates that the medication is to be administered through the rectal route, which is commonly used for certain types of medications, including suppositories and enemas. The rectal route can be beneficial for patients who are unable to take medications orally due to various reasons, such as vomiting or difficulty swallowing.

In contrast, the other options represent different routes: "pv" stands for "per vagina," indicating a vaginal route of administration; "ac" means "ante cibum," or before meals, often used to describe the timing of oral medications; and "pc" stands for "post cibum," or after meals. By understanding the specific meanings of these abbreviations, one can accurately identify the method of administration intended for a given medication.