I was curious on an actual scientific idea of death so I had asked two of my professors in different fields (One in biology and the other in chemistry) and I liked the difference in opinions based simply on the variation of their studies.
My biology professor said:
Death is when all functions to sustain a living being halt and there is a 0 percent chance of recovery from this state.
While my Chemistry Professor said:
Death is the loss of the connection between the mind and body. (Thus implying brain dead victims being defined as dead)
This may hold little to no significance to this topic but I just find it amusing that the mere definition of death is changed simply because of the different levels of actual science you teach.