Definition:Adjacent


 * Adjacent (Graph Theory):
 * Two vertices are said to be adjacent there exists an edge to which they are both incident.
 * Two edges are said to be adjacent there exists an vertex to which they are both incident.
 * Two faces of a planar graph are said to be adjacent or neighboring there exists an edge to which they are both incident.


 * Adjacent (Geometry):
 * Two angles are adjacent they share a line. Similarly:


 * Adjacent in Polygons:
 * The two sides of a polygon that form a particular vertex are adjacent to that vertex.
 * The two vertices of a polygon that terminate a particular side are adjacent to that side.
 * Two sides of a polygon that meet at the same vertex are adjacent to each other.
 * Two vertices of a polygon that terminate the same side are adjacent to each other.


 * Adjacent in Polyhedra:
 * The faces of a polyhedron that form a particular vertex are adjacent to that vertex.
 * Two vertices of a polyhedron that meet at the same face are adjacent to that face.
 * The faces of a polyhedron that form a particular edge are adjacent to that edge.
 * Two edges of a polyhedron that meet at the same face are adjacent to that face.
 * Two faces of a Definition:Face of Polyhedron|faces that meet at the same vertex are adjacent to each other.


 * Adjacent (in a Triangle): The two sides of a triangle that form a particular vertex are adjacent to that vertex. Usually used in the context of right triangles:
 * Adjacent (in the context of Trigonometry): The adjacent side of a given right triangle $\triangle ABC$ with respect to one of the non-right angles $\angle A$ is the side of the right triangle adjacent to $A$ which is not the hypotenuse.

Also see

 * Definition:Separated
 * Definition:Opposite