What is the difference between atherosclerosis and arteriosclerosis?

None: They are used to describe the same thing.

None: They are two different terms for the same thing. Atherosclerosis is the formal term. Arteriosclerosis is an older less formal term.

Largely Nothing: 2 different words for largely the same disease process. Disease (a) typically starts in later childhood, is (b) due to an accumulation of white blood cells in the walls of the arteries, (c) no symptoms occur for decades, though arteries get stiffer (d) most events are without symptoms (despite tissue damage) when symptoms finally do occur, they are commonly of sudden onset due to plaque rupture.