It is the death of a brain cell
that qualifies as a stroke.
There are a myriad of ways that stroke (aka cerebral infarct) can happen; hypoglycemia
(low blood sugar
), hypoxia (low blood oxygen), obstruction of blood supply or excessive tissue pressure (clots or bleeding); all of which can lead to the death of a brain cell.
Previous names used described the mechanism of brain cell death (cerebral vascular accident [CVA]) or distress (transient ischemic attack
[TIA]). Strokes are generally diagnosed by CT (cat scan) of the head, as the dead area shows up differently from living brain tissue.