Here are some possibilities:
* Misspelling: Perhaps you meant "paragon" which means a model of excellence or perfection.
* Specialized Terminology: It's possible "paradian" is a technical term in a specific field like science, engineering, or even a specific dialect or language.
To help me understand what you're looking for, could you please provide more context? For example:
* Where did you see or hear the word "paradian"?
* What was the topic of discussion?
* What is the general meaning you associate with the word?
With more information, I can try to help you find the right term or understand its meaning.