Definition:Opposite


 * Geometry:
 * Opposite (in a Polygon):
 * The opposite side (or angle) to a given side is that side (or angle) which has the same number of sides between it and the side in question.
 * The opposite side (or angle) to a given angle is that side (or angle) which has the same number of sides between it and the angle in question.
 * Opposite (in a Triangle): The side of a triangle which is not one of the sides adjacent to a particular angle is referred to as its opposite. Thus, each angle has an opposite side, and each side has an opposite angle.


 * Solid geometry:
 * Opposite face: In a parallelepiped, the face which is parallel to a given face is the opposite face to that face.


 * Group theory:
 * The opposite group to a group $\left({G, \circ}\right)$ is the group $\left({G, *}\right)$ defined such that $\forall a, b \in G: a \circ b = b * a$.