On Wed, 2001 Sep 19, Bill Hooper wrote: > > ... I still do not understand why I may not call the centimetre a unit, > using the dictionary definition of the word "unit". ANS: Declarations by the CGPM (summarized in the BIPM Brochure) are the authority for SI. No group of dictionary editors (however distinguished, anywhere) are a substitute for the CGPM as *the authority* for SI. The BIPM Brochure *emphasizes* that there is only one SI unit for each physical quantity. For the unit of length, only the "meter" is the SI "unit" of length. In SI, the "centimeter" is a "submultiple" of the meter, but not an SI "unit" per se. On the other hand, if you prefer to work *outside* the SI, with older "cgs units", the centimeter is indeed the "unit of length" in cgs units, but cgs units must not be confused with SI units. Gene.
