|How Many? A Dictionary of Units of Measurement
© Russ Rowlett and the University of North Carolina at Chapel Hill
This dictionary includes:
Each unit's definition includes conversion factors you can use to convert that unit into other units measuring the same concept. In the case of the traditional units, remember that in many cases the "precise" definition for an older unit (such as the league or the hogshead) was not established until the nineteenth century. It's not wise to rely too much on these definitions when reading older works. Also, many units which have precise meanings now, such as the barrel and the gallon, formerly had a variety of special meanings when applied to particular commodities; there isn't space in the dictionary for all these meanings.
For many units, an abbreviation or symbol is given in parentheses, like this: gram (g). Generally speaking, symbols do not appear as separate entries, except in those cases where one could not guess from the symbol which page the unit appears on. So if all you know is a symbol or abbreviation, it's necessary to scan the appropriate page and search for the abbreviation. For example, for the unit abbreviated "Pa" look on the "P" page.)
It is often necessary to use scientific (powers of ten) notation, like this: 106. If that doesn't show up on your screen as 10 raised to the 6th power, then similar problems will occur throughout the dictionary.
In addition, there are several Greek letters used as symbols. Most Internet browsers use Unicode encoding and will display the "micro" symbol µ (lower case Greek letter mu) and Greek letters such as π (lower case pi), γ (lower case gamma), and Ω (capital omega).
The dictionary observes certain standard conventions on using numbers and units.
The dictionary contains a huge number of links intended to cross-reference between units. If you find such a link that doesn't work, please let me know so I can fix it.
Return to the Dictionary Contents page.
You are welcome to email the author (firstname.lastname@example.org) with comments and suggestions.
All material in this folder is copyright © 2004 by Russ Rowlett and the University of North Carolina at Chapel Hill. Permission is granted for personal use and for use by individual teachers in conducting their own classes. All other rights reserved. You are welcome to make links to this page, but please do not copy the contents of any page in this folder to another site. The material at this site will be updated from time to time.
January 6, 2000; latest update July 14, 2004.