1. As a name:
* "Roo-uhn" is the most common pronunciation, especially in fantasy contexts like Tolkien's works. It's similar to the way you would pronounce "rune."
2. As a Welsh word:
* "Rhoon" with a short "oo" sound, similar to the word "moon" is the more accurate Welsh pronunciation.
Ultimately, the correct pronunciation depends on the intended meaning and context.