Coins are measured in millimetres.
Millimetres, as in 1.5 mm. You could use a micrometer to measure thickness of a coin.
You could describe that measurement accurately and precisely with any unit of length.But the 'millimeter' would probably produce the most convenient number.
a vagina
Use dry measure measuring cup.
Units of measurement are useful to rationally measure anything.
you would use a kilogram
use a tape measure or some form of measurement to measure you ;]
inches
a meter
inches
Joules