Which of the following roots signifies 'fat'?

The root "ather/o" signifies 'fat.' In medical terminology, "ather/o" is derived from the Greek word "athere," meaning gruel or porridge, which historically referred to the fatty deposits found in arteries. This term is commonly used in contexts related to atherosclerosis, a condition characterized by the buildup of fatty plaques in the arterial walls, leading to cardiovascular diseases.

Other root terms, such as "audi/o," pertain to hearing, as seen in words like "auditory." "Atri/o" relates to the atria of the heart, while "articul/o" refers to joints or the process of articulation. Each of these roots has specific meanings that are distinct from fat, clearly illustrating why "ather/o" is the appropriate choice for signifying 'fat.'