The Oxford English Dictionary has, appropriately enough, a long and complicated definition for the word "place." For the purposes of this discussion, we should focus on the following portions:

a particular spot or area inhabited or frequented by people ... a particular part or region of space; a physical locality ... a region or part of the earth's surface

For the purposes of data modeling in Pleiades, we define a Place as a collection of geographic locations, names and related information that, in aggregate, conform to some part of the definition above.