The short horizontal line is used as an electrical sign to indicate
or intended for direct current.
When is placed above another sign it raises or increases or multiplies that sign's meaning. If placed under another sign it serves to accentuate or multiply that sign's meaning. If, on the other hand, it appears between two other signs, it unites them or their denotations, as opposed to , which separates and divides. The latter spectrum of meaning can be most clearly illustrated by the minus sign in mathematics, which links two numbers in a special way, or by for unmarried.
But can as well as also separate signs, for example when it appears as a dash.
The short horizontal line, especially before or in another sign, cancels or negates it (except when used as a hyphen in typography and writing). For example, in the traffic sign with the structure , the line cancels empty circle's endless possibilities for traffic. In logic and chemistry as in mathematics is used for negative. In mathematics it is the minus sign. In music this sign is used to indicate a minor cord, e.g. -A7. It stands for south in astronomical and nautical systems, whereas in electrical and electronic contexts it represents the negative pole or terminal.