Background: Patients who undergo ultrasound examinations are three-dimensional structures. Although the output is a B-mode image, we do not think of it as a two-dimensional object. Hence, use of the expression “spherical” mass is favorable. On the other hand, the expression “circular” mass is inconsistent. Misuse of the medical ultrasound terminology: A retrospective analysis of papers reported in the Jpn J Med Ultrasonics or JSUM meetings disclosed misuse of the following medical ultrasound terminology: “periphery,” “border,” “contour,” and “adjacent zone,” resulting in confusion among them. In particular, confusion between “periphery” and “contour” is noteworthy. The situation could lead to a confused discussion associated with misunderstanding of the ultrasound findings. Conclusion: It is important that results of medical studies are conveyed through correct medical terms and proper expressions because misunderstandings could be a barrier to progress.