Final answer:
A ballooning of an arterial wall is called an aneurysm, a potentially dangerous condition that can lead to a rupture and life-threatening bleeding. It is distinct from an embolism, blood clot, or angioma.
Step-by-step explanation:
A ballooning of an arterial wall is called a aneurysm. This condition occurs when part of an artery wall weakens, allowing it to widen abnormally or balloon out. An aneurysm can be dangerous because it can lead to a rupture, causing life-threatening internal bleeding. While an embolism is related to an obstruction in the blood flow due to a dislodged blood clot or air bubble, and a blood clot is the solidification of blood within the vascular system preventing proper blood flow, these are different from an aneurysm. An angioma is a benign growth that consists of small blood vessels and is unrelated to the ballooning of arterial walls.