The girth of a sphere in any direction equals the circumference of its equator, or of any of its great circles.
In some application areas such as shipbuilding this alternative meaning, the perimeter of a cross section, is taken as the definition of girth.
[3] Girth is sometimes used by postal services and delivery companies as a basis for pricing.
For example, Canada Post requires that an item's length plus girth not exceed a maximum allowed value.
[4] For a rectangular box, the girth is 2 * (height + width), i.e. the perimeter of a projection or cross section perpendicular to its length.