Billit in most cases as far as I know refers to items cut from one piece of alluminum. All of those shiny trinkets you see attached to cars that are called billet are cut from one piece of alluminum. Rims, trim, shift knobs whatever.

Don't you know who I think I am?
I've been thinkin' about freaking out. If I could just find the time.
http://community.webshots.com/user/ifrizlfri