Symbols and abbreviations

Only symbols and abbreviations related to measurement

The index only covers symbols and abbreviations for units. Many, maybe most of these strings of letters have a completely different meaning in other areas. For example, “ccd” following a measured value means centicandela, but in talk about digital cameras it stands for “charge-coupled device”, and though that is a far more frequently encountered meaning, you won't find it here.


Usage has changed. For example, in the first part of the 20th century, the abbreviations of the names of units in the metric system were followed by a period. Since 1960, they are not, according to the rules of the CGPM. In general, the tendency lately has been to do away with periods. If you enter an abbreviation with a period, the search engine will check to see if a period-free version is available, and vice-versa.

Upper and lowercase

Case is important. For example, m for milli and M for mega differ by a factor of 1,000,000,000. Some editors have stupidly printed glossaries in all caps, destroying meaning. If you enter a term in all caps, and the search engine doesn't find that term, it will suggest some possibilities containing lowercase letters. Unfortunately it must be up to you to decide if any of those meanings are appropriate.


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