Definition:Opposite Sides of Symmetric Figure

Definition

Let $F$ be a geometric figure with a center of symmetry $S$.

Two sides of $F$ are opposite if and only if they are joined by a straight line through the center of symmetry of $F$.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): opposite: 2.
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): opposite: 3.