* A misspelling: It could be a typo of a different word.
* A specific term: It might be a term specific to a particular field, hobby, or cultural context.
* A made-up word: Perhaps it was invented for a fictional story or game.
To understand the meaning of "oyaheya", you'll need more context. For example:
* Where did you hear it? Was it in a book, a movie, a conversation, or online?
* What was the context? What was being discussed or happening when you heard this word?
Providing more information will help me understand what "oyaheya" means.