* A misspelling: There might be a similar word you're thinking of. Could you be thinking of "veteran"?
* A specific term: It's possible "vetterian" is a term used in a particular field, hobby, or community. If you can give me more context (e.g., where you heard it), I might be able to help.
* A made-up word: It's also possible it's a completely made-up word.
Could you please provide more information so I can help you understand what "vetterian" might mean?