* A misspelling of a different word.
* A name of a person or place.
* An abbreviation for something.
* A brand name (Tyan is a manufacturer of motherboards).
To understand what "Tyan" means in your context, please provide more information, such as:
* Where did you encounter this word? (e.g., a book, a conversation, a website)
* What was the context?
* What language are you interested in?
With more context, I can help you find the correct meaning.