[simiones]

A memory leak has always meant "this program keeps allocating more memory as it runs, even though it's not being asked to store anything new". That is equivalent to saying that a program has a memory leak when it fails to free memory that is no longer needed, not just memory that is no longer reachable.

For example, a common example of a memory leak is adding items to a "cache" without any mechanism that evicts items from the cache in any scenario. The "cache" is thus not a cache, but a memory leak (a common implementation of this leaking scenario is that items are put in a map, but never removed from the map).

Memory leak has never, as far as I know, referred to the specific case of memory that is no longer accessible from program code to be freed. In fact, this definition doesn't even make sense from a runtime system perspective, since even in C, the memory is actually always still reachable - from malloc()'s internal data structures.