Pronunciation: /ɛdʒ/ ?

Geometric figure with dotted boundaries and solid boundaries.
Figure 1: Edges of a geometric figure.

  1. An edge of a 2-dimensional geometric figure is the boundary of the figure.[1] The figure does not extend beyond the boundary. The word 'edge' is usually used to refer to a straight edge. However both 'edge' and 'boundary' can be used to refer to a curve.
  2. An edge of a 3-dimensional polyhedron is the line formed by the intersection of two faces.
  3. An edge of a network graph is a path joining two nodes.

A boundary may or may not be included in the object. When graphing, a boundary that is not included in the object is conventionally drawn with a dotted line. A boundary that is included in the object is conventionally drawn with a solid line.


  1. edge. http://wordnet.princeton.edu/. WordNet. Princeton University. (Accessed: 2011-01-08). http://wordnetweb.princeton.edu/perl/webwn?s=edge&sub=Search+WordNet&o2=&o0=1&o7=&o5=&o1=1&o6=&o4=&o3=&h=.
  2. Stöcker, K.H.. The Elements of Constructive Geometry, Inductively Presented, pg 47. Translated by Noetling, William A.M, C.E.. Silver, Burdett & Company, 1897. (Accessed: 2009-12-31). http://www.archive.org/stream/elementsofconstr00noetrich#page/47/mode/1up.

Cite this article as:

Edge. 2010-08-05. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/e/edge.html.


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Revision History

2010-08-05: Added edge of a polyhedron and edge of a network graph. (McAdams, David.)
2009-12-31: Added "References" (McAdams, David.)
2008-12-17: Initial version (McAdams, David.)

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