This is about the objective interpretations/assessment/quantification of riddles. Let us define a riddle as a type of puzzle relying on the usage of only language and context. 

Using precise English as a formal (non-opinion based) tool, and examples and sources like dictionaries, grammar sources (ELU.SE maybe), and perhaps literature (e.g. The Hobbit), or even possibly sources from this SE, explain how to construct and what defines a "solid" Riddle? 

I might expect that the answer might contain something like: a "solid" Riddle should have one and only one interpretation which coherently addresses each line/clue contained in the Riddle. 

**Related:**  

[Question about writing rhyming riddles.](https://puzzling.stackexchange.com/questions/105/how-do-you-come-up-with-a-good-classic-rhyme-riddle)  

[Tips for solving riddles.](https://puzzling.stackexchange.com/questions/4574/tips-for-solving-poem-riddles?lq=1)