Atherosclerosis refers to the buildup of fats, cholesterol and other substances in and on your artery walls (plaque), which can restrict blood flow.
https://www.mayoclinic.org/diseases-conditions/arteriosclero...
An atheroma, or atheromatous plaque ("plaque"), is an abnormal accumulation of material in the inner layer of the wall of an artery; it is present in the arteries of most adults.[1] The material consists of mostly macrophage cells,[2][3] or debris, containing lipids, calcium and a variable amount of fibrous connective tissue.