I think Kix is right here. A "unit" can be an inch, a centimeter, or an Angstrom, or a mile; so long as you don't try to mix them in the same document it doesn't really matter.
The "ancient British stuff etc" are called imperial units.
Not that I think they're especially "regal". :-) Ooops Carrara doesn't do Angstroms. Now there's an oversight!;-)

Message edited on: 04/21/2005 16:10