What prefix indicates "two" or "double" in medical terminology?

The prefix that indicates "two" or "double" in medical terminology is "dipl-." This prefix is derived from the Greek word "diplous," meaning double. It is commonly used in medical terms, such as "diplopia," which refers to double vision—a condition where a person sees two images of a single object. Understanding this prefix can help in deciphering various medical conditions and terms that involve the concept of a pair or duplication. The other prefixes have different meanings: "hemi-" signifies half, "mono-" indicates one or single, and "multi-" refers to many or multiple.