How wide of a snowboard do I need?  Where is the width of a snowboard measured?  What does width mean in terms of my boot  size?

Let’s start by talking about measurements, because this is where a lot of the confusion arises.  The most common width measurement that is provided by manufacturers is "waist".  The waist is measured at the narrowest point near the middle of the board (usually). But like with all things in snowboarding, different brands measure different things. Some measure  the midpoint between the tip and tail and call that "waist". Others simply provide a measurement they call, "width", but do not really specify what width they are referring to.