Which term represents an abnormal narrowing of a structure?

The term that represents an abnormal narrowing of a structure is indeed "-stenosis." This suffix is derived from the Greek word "stenos," which means narrow. In medical terminology, -stenosis is commonly used to describe various conditions where a passage or opening in the body is constricted, which can lead to various complications depending on the structure involved. For example, "arteriostenosis" refers to the narrowing of an artery, which can impede blood flow and lead to serious health issues.

The other terms do not convey the same meaning. The suffix "-osis" refers to a condition or disease, which does not specify any narrowing. "-megaly" denotes an abnormal enlargement of an organ or structure, indicating an increase in size rather than a decrease. "-dynia" refers to pain, which does not pertain to structural narrowing. Understanding these distinctions helps clarify why -stenosis is the correct choice in this context.