From AMS Glossary
Revision as of 19:43, 26 January 2012 by Perlwikibot
May be applied to any property of a physical system that can take on only two values, usually opposite in some sense (e.g., sign or direction).
Thus, the electron and positron are said to have opposite polarity because their charges are equal in magnitude but opposite in sign. Similarly, anodes and cathodes are electrodes of opposite polarity.