Is abdominal aortic aneurysm the same thing as aortic dissection?

No. : Dissections may become aneurysmal. An abdominal aortic aneurysm is a full thickness dilatation of the aortic wall. In a dissection, there is a tear of the intima and the blood then shears the layers appart crating either 2 lumens or a mural hematoma or both.

No: Can happen together on occasion. Usually AAA does not "dissect" which is an intramural tear and hematoma. Other non aneurysmal vessels may tear with hypertension or degenerative vessel wall.

AAA v dissection: Not really; an aneurysm bulges due to a weakness in the artery wall. A dissection is a tear in one or more ( of the three) layers of the artery wall which continues in one or both directions.