Dimension

Pronunciation: /dɪˈmɛn ʃən/ ?

A dimension is an extension in a particular direction.[1] A line has one dimension, since it extends in only one direction. A two dimensional space has two dimensions. An x-y graph is two dimensional. The x-axis defines one dimension and the y-axis defines another.

A dimension is not necessarily length. A dimension may also be temperature, time, mass, electrical current and others. For example, an equation may relate time and temperature: p = 2.5t where p represents temperature and t represents time. In this equation, one dimension is time and the other dimension is temperature. Albert Einstein's special theory of relativity deals with four dimensions: three dimensions are lengths making up a space, and one dimension is time. See also Dimensional Analysis.

Dimensionless

An object is said to be dimensionless if it has no dimensions. The only object in most geometries that is dimensionless is a point.

Dimensions
Number
Dimensions
ManipulativeDescription
0 Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A point has no dimensions.
1-D
1 dimensional
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A line has one dimension.
2-D
2 dimensional
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A two-variable Cartesian coordinate system has two dimensions.
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A rectangle has two dimensions (length and width).
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A circle has two dimensions (length and width).
3-D
3 dimensional
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A sphere has three dimensions (length, width, and height).
Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now) A rectangular solid has three dimensions (length, width, and height).
4-D
4 dimensional
Euclidean space has four dimensions (length, width, height, and time).
Table 1: Dimensions

More Information

  • McAdams, David. Space. allmathwords.org. Life is a Story Problem LLC. 2009-03-12. http://www.allmathwords.org/article.aspx?lang=en&id=Space.
  • McAdams, David. Dimensional Analysis. allmathwords.org. Life is a Story Problem LLC. 2009-03-12. http://www.allmathwords.org/article.aspx?lang=en&id=Dimensional%20Analysis.

Cite this article as:


Dimension. 2010-01-23. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/d/dimension.html.

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Revision History


2010-01-23: Added "References" (McAdams, David.)
2009-11-22: Added manipulatives. (McAdams, David.)
2008-07-11: Added table of dimensions (McAdams, David.)
2008-07-07: Corrected spelling errors (McAdams, David.)
2008-05-07: Added discussion of non-length dimensions (McAdams, David.)
2008-03-10: Initial version (McAdams, David.)
2008-01-28: Added link to Albert Einstein biography (McAdams, David.)

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