How do you spell bussiom?

"Bussion" is not a recognized English word. It's possible you're thinking of a different word, or there might be a typo.

Could you please clarify what you mean?

For example, do you mean:

* "Button"?

* "Bussion" (a specific term you've heard or seen)?

* "Bus"?

Once you tell me what you're looking for, I can help you with the correct spelling.