Scale
Also said as Compressed space, Game scale
How big the world claims to be against how big it actually is. Game worlds are heavily compressed: a capital of thousands is a few streets, and a kingdom takes an afternoon to walk.
Compression is fine, and it is needed, because real distances are boring. Trouble comes when the words and the space disagree: a "great city" with twelve houses reads as a joke unless you handle it.
Say it
“Never give a number for the city's population. Say "the city" and show forty houses. If a book must mention it, write "a few hundred souls".”
Where you’ve seen it
Whiterun in Skyrim is treated as one of the great cities of its province and is only a handful of streets. Players accept it, because the game's mountains, music and sparse wilds all make the walk there feel long.
Not to be confused with map size
Map size is a number on a design document. Scale is how big the place feels, and that depends on what fills it and how long it takes to cross.