How Many? A Dictionary of Units of Measurement
Controversies arise sometimes over the spelling of metric units. In many cases, these controversies grow out of a misunderstanding as to just what is international in the International System of Units (SI).
The fact is that the spellings of SI units vary from one language to another. In the case of the U.S. and Britain, spellings differ even within a language: Americans write meter and liter while the British write metre and litre.
The variation in spelling, however, goes much farther than that. Even if we disregard accent markings, the fundamental SI unit of length has numerous spellings, including:
No doubt this list could be extended quite a bit. The point is, there is no "official" spelling of the SI units. What the SI does provide includes the names, the definitions, and the symbols of the units. The words meter, metr, metre, etc. represent the same name spelled in different languages.
Within the International System, Russians are welcome to call 1000 meters a kilometr, but they cannot call it a verst, because that would be a different name. The Italians call the same unit the chilometro, but they cannot make its symbol chm; they must use km.
June 4, 1999