Vulnerable plaque, a term used in medical sciences, refers to the development of atherosclerotic lesions in the arterial walls that are prone to rupture and cause sudden blockage or blood clot formation. There are several synonyms to describe these types of plaques, including unstable plaque, rupture-prone plaque, high-risk plaque, and thin-cap fibroatheroma. These terms are used interchangeably to describe the plaques that are likely to cause cardiac events such as myocardial infarction (heart attack) or stroke. It is important to identify these vulnerable plaques in patients with cardiovascular diseases to initiate timely interventions and reduce the risk of morbidity and mortality.