Here is a cartographic term that has been talked about extensively, but not necessarily defined. Generic. This refers to the descriptor attached to place names. Examples: In Rocky Mountains, the generic is "Mountains". In Rio Grande, it is Rio. "Rio" and "mountain" and "Wadi" and "erg" aren't really cartographic terms in themselves. I believe the US Board on Geographic Names has a list of generics used in the US. I'll see if Icahn track it down.
Couldn't find the link I was looking for but I found these which are kinda cool. I posted them here even though it relates more to "toponymy" ( the study of place names) than it does to Cartography.
List of generic forms in place names in the United Kingdom and Ireland - Wikipedia, the free encyclopedia
Generic terms – Antarctic Place-names Committee
I apologize if they have already been posted.
I'm going to throw a few of these terms around at the next party I go to an see if it impresses anyone! lol