A puzzle, or puzzle aspect, using literary devices and word play
A riddle is a lingual puzzle where understanding the semantics of the words used is required to find an answer. The answer could be encoded within the words themselve, it could be a trivia question, or it could be a clue to a further puzzle.
I stand upon four legs, but when you think of me, you think of sitting. What am I?
The puzzle is a trivia puzzle, as it's asking what has four legs and is used for sitting. It's presently with some word play though, intentionally drawing on abiguity of meaning to hide the simple answer. <i>The answer is "chair".</i>
A riddle could also refer to words, or letters within itself, for example:
Long have I stood, as the first and the last, then only the three, the rest I shall abandon.
This riddle talks about the sentence itself, requiring you to piece together the parts. Without knowing what they are looking for, the player may have a hard time knowing if they are correct. Thus word play riddles need to be have fairly obvious answers, or have a good deal of context. A reasonable hint here would be: it's a city.
As a lingual puzzle, riddles can be highly language specific, even regionally limited with local dialect. As a trival puzzle, they may also be regionally limited, should they use local concepts. Highly regional riddles need to be localized to each audience that is expected to play it.
Riddles can however appeal to a wider audience, using a limted amount of terminology as well as global, or well known concepts.
Assume everything in this reference is a working draft, there's prone to be some mistakes and inconsistencies. I figure it's best to publish and get feedback rather than write for years in secret. The terms will change, the structure will shift, and the bugs will be chased out. It'll take a while.