[avmich]

The confusion comes from naming American units "imperial" - after British, and having international - metric - system created by the French revolution, with "liberte" an important goal. So it could be argued that it's actually SI which has freedom units. On the other hands, Americans are quite often characterized as freedom "distributors"...

[jdblair]

The American system is called "customary units." The pint, quart and gallon are all smaller than British imperial versions.

[kwhitefoot]

Most Americans that I have pointed this out to look at me in disbelief. The vast majority have never heard of US Customary Units. Whenever they refer to their system of measure they say imperial, and many are unaware that volume measure in the Imperial system is different from US Customary. I fought again the use of imperial as the name for the system for over twenty years in a multinational company to no avail.

[jdblair]

Send them this handbook from NIST! :) Section 2 covers all of the customary measurements, some with names hardly anyone knows (Apothecaries Units? Gunter's Chain Units?)

https://www.nist.gov/system/files/documents/pml/wmd/pubs/201...

[kwhitefoot]

NIST is also a good source for information about SI!

[jrmg]

American units of volume are different (most smaller by about 20%) to Imperial units.