A great many of the ideas on this Wiki would, in the days before the interwebs, have been referred to by literary critics as conceits.
In literature, a conceit is an idea, collection of ideas, metaphor, structure, or other imagined device which defines or enables the world of the story, or some action in it. Conceits can be obvious; if a book is about space explorers who question their humanity upon discovering life on Mars, the conceit is that there is life on Mars. Originally the term was used much more specifically, to refer to a deliberately chosen juxtaposition that rarely or never occurs naturally (life/Mars), used as a means of revealing the unique properties of the items or ideas being juxtaposed. Its usage has become much broadened. A good example of a trope that is also a conceit is any trope of the form Our Xs are Different.