Dead is when there is no brain activity. Is there any record of anyone coming back to life after they had no brain activity?
Lots of reports of people coming back to life after the 'official' time of brain death (7 minutes without blood flow I think) but of course that is not what I'm talking about.
Through their writing, I have come to respect several men who report that they saw Jesus after his body, and presumably his brain, was certifiably dead. I don't think they were lying.
It created quite a stir. We're still talking about it 2000 years later.