Which term refers to someone who outlives another person or event?

The term that best describes someone who outlives another person or event is "survivor." In the context of loss or death, a survivor is an individual who continues to live after someone has passed away. This term captures the essence of endurance and continuing existence following a significant loss, whether it involves personal relationships or broader contexts such as traumatic events.

In contrast, an 'heir' pertains specifically to a person who is legally entitled to inherit the property or title of another upon their death. A 'beneficiary' is someone who receives benefits, especially in the context of insurance or estate planning, but does not necessarily imply having outlived someone. Meanwhile, a 'mourner' is someone who expresses grief, typically at a funeral, but this term does not focus on the aspect of living beyond another individual or event. Thus, 'survivor' is the most accurate term to denote an individual who has outlived someone else.