American National Standard Letter Symbols for Units of Measurement (SI Units, Customary Inch-Pound Units, and Certain Other Units)
|Publication Date:||1 January 1993|
This standard covers letter symbols(Footnote 1) for units of
measurement. It does not include
abbreviations for technical terms, nor does it cover symbols for
The symbols given in this standard are intended for all applications, including use in text and equations; in graphs and diagrams; and on panels, labels, and nameplates.
Footnote 1 - "Letter symbol" as a technical term does not have the same meaning as either "name" or "abbreviation." An abbreviation is a letter or a combination of letters (plus sometimes an apostrophe or a full stop, i.e., a period) that by convention represents a word or a name in a particular language; hence, an abbreviation may be different in a different language. A symbol represents a physical quantity or a unit and is therefore independent of language. For example, the symbol for electromotive force is E, whereas the abbreviation is emf in English, fem in French, and EMK in German. The unit names "ampere" and "second" have sometimes been abbreviated amp and sec, respectively, but this usage is now deprecated. The standard unit symbols for ampere and second are A and s, respectively.
Footnote 2 - As used in this standard, the term physical quantity means a measurable attribute of phenomena or matter. Examples are length, mass, and time.