On Sun, 28 Apr 2002, Bill Hooper wrote: > ... > I don't see how (or why) it can be said that the exametre is not a unit.
The "exameter" is a "multiple" but not an "SI unit" because CGPM resolutions (quoted in NIST SP 330 (2001 Edition) and in the BIPM Brochure (1998 Edition)) *define* the SI in that way. Simply say "SI" when you want to include SI base units, SI derived units, and SI units which carry SI prefixes. That's easy! You might want to include or exclude one or more of the several numbered Tables of "Non-SI" units approved for use with the SI in your use of the acronym "SI" when you teach or discuss the subject of defining the SI. I'm aware that the CCU wants to redefine the semantics of the SI, but neither the CIPM nor the CGPM has approved suggested changes. Until revised semantics become official, the BIPM Brochure (and SP 330-2001) define the SI. Gene.
