What does the abbreviation "AD" represent in a medical context?

In a medical context, the abbreviation "AD" stands for "Right ear." This abbreviation originates from the Latin phrase "auris dextra," which translates directly to "right ear." In prescriptions or medical records, this shorthand is commonly used to specify that the treatment, medication, or procedure is intended for the right ear specifically. This is essential for clear communication in patient care, as misinterpretation could lead to administering treatment to the wrong ear, potentially causing harm or ineffective treatment.

The other options refer to different meanings within medical terminology. "Left ear" is denoted by "AS" (auris sinistra), "both ears" is expressed as "AU" (auris utraque), and "twice a day" is abbreviated as "BID" (bis in die). Each of these terms has its designated abbreviation, making it important to use them accurately to avoid confusion in clinical settings.