aneurysm UK /ˈan.jʊɹ.ɪz.əm/US /ˈæn.jəɹ.ɪz.əm/ noun1 •An abnormal blood-filled swelling of an artery or vein, resulting from a localized weakness in the wall of the vessel.Give me a swift death, she thought — a hammer blow to the head, the sudden aneurism, the proverbial bus. — 2024 formsaneurysms