Anatomically, it is linear with your belly button...at birth. After aging and babies and whatnot, who the hell knows where your waist really goes! You will find descriptions for jeans and pants that say "sits just below your waist" or "sits at the waist" or "sits at the natural waist"...okay...in the picture on the model or drawing, we can pretty much see where her waistline is considered to be, but for many of us....well, whatever. Some people are "long waist-ed" which means they have a longer torso and visa versa for short waist-ed ladies. Trying on clothing for fit, especially if they have a belt or tie, is very important. Our pictured blouse has an attached tie belt that sits above what would call the natural waistline but below the "empire" waist level, or the area located just below the bustline. Why is this? Well the belt is made from the former sleeves and the curve of the side seams dictated a natural spot for their location to avoid bulk above or below the attachment point. No diagram can really describe a fit. Online shopping for one of a kind pieces is not easy, but we are willing to work with you one on one for finding a good match and a great fit.