Is there an elegant one-word english term for datums made of a combination of (meeting) time (span or point) and place?
Naturally you could say "time and place of ...", but when you speak of a meeting, you normally want to refer to them both at a time.
Well apart from bikeshedding your variable names this isn't such a bad question actually.
In physics space and time are considered to be aspects of the same thing, called spacetime.
One term I've seen used to describe something located in spacetime is event, but this term already has enough meanings (especially in computing). Here are some places the Wikipedia article uses this term:
In cosmology, the concept of spacetime combines space and time to a single abstract universe. Mathematically it is a manifold consisting of "events" which are described by some type of coordinate system. Typically three spatial dimensions (length, width, height), and one temporal dimension (time) are required.
For example, on the globe the latitude and longitude are two independent coordinates which together uniquely determine a location. In spacetime, a coordinate grid that spans the 3+1 dimensions locates events (rather than just points in space), i.e., time is added as another dimension to the coordinate grid.
Spacetimes are the arenas in which all physical events take place—an event is a point in spacetime specified by its time and place.
The basic elements of spacetime are events. In any given spacetime, an event is a unique position at a unique time.
Apart from that you will also see point in spacetime and location in spacetime used.