system agnostic – What does it mean for a word or phrase to be a “game term”?

These two questions use the phrase “game term”:

Both answers seem to make a distinction between game terms and regular English, but what exactly does it mean for a word or phrase to be a “game term”?

I will admit, when I first read the question in the first bullet above, I thought to myself “of course it’s a game term, it’s a term, and the rules of the game use it”, but apprently, that is not correct.


Note, there are many other examples of Q&As (about games other than D&D 5e) that make this distinction, see these search results for more.