if i define a plane by 3 points is that a plane that exists infinitely and those three points just happen to be 3 within it, or do those 3 points define the bounds of the plane?

It seems like that defines the bounds based on experimentation.

If so does anyone know if a plane which is defined not by 3 points but just by 1 point a normal (which since a plane requires 3 points at minimum to be of a defined size)

is infinite?