I am looking for a term to describe the widest part of an ellipsoid. However this ellipsoid is irregularly shaped because it's a wine glass. As the glass goes up from the stem it continues to widen and then toward the brim it begins to narrow again just a little. So basically it is an ellipsoid which is cut off at one of the ends of it's Z-axis. I was wondering of anyone knew the name of the point where it begins to narrow again.