Which term denotes "after death"?

The correct term that denotes "after death" is "post mortem." This phrase is derived from Latin, where "post" means "after" and "mortem" means "death." In various contexts, such as in medical and legal settings, "post mortem" is used to refer to examinations that occur after an individual has passed away, most commonly relating to autopsies that determine the cause of death.

The other terms, while having distinct meanings, do not relate to the concept of "after death." "Post hac" refers to actions that occur after an event but does not specifically connect to death. "Pro forma" indicates something done as a formality or for the sake of appearance without it necessarily being meaningful or substantive. "Pro rata" concerns proportional distribution or allocation, often used in financial contexts, and again does not connect to death. Thus, "post mortem" is the only term that accurately reflects the essence of "after death."