The British Standard Handful, or BSH, is a measurement of breast size.
It is a pure measure of volume; issues of shape and form must be
considered separately.
One BSH is defined as the amount of breast that could be held by Henry
VIII's right hand. In the same way that the average foot is less than a foot
in length, the 'British Standard' handful is noticeably larger than the standard
British hand. This is not necessarily a bad thing — after all, being
short changed is more disappointing than receiving slightly more than
anticipated.
The BSH is a far more convenient unit for real world use than its metric equivalent, the cubic metre. Just as it is far easier to ask
for a pint of beer than 0.568 litres, one BSH is a much more manageable
quantity than 3.1*10-4m3 or 310cm3. This is one
of the reasons that the imperial system remains more popular for measuring
breasts (the other being that physicists have little to no use for this
unit).
In its pure form, the BSH refers to the size of an unrestrained, unsupported
breast in its natural state. However, with the appropriate qualifiers it can
also be used in refer to apparent size after enhancements (for example,
via a padded bra).
In the United States, the Britney is the more popular unit.
Unfortunately, the value of the Britney fluctuates depending upon season and
outfit. Nor is there a standard Britney locked in a hermetically sealed vault
in Paris — this is very much a unit which can be adapted to suit the
occasion rather than an objective measure.