• geometry
    at a right angle to the line, surface, or plane.
All terms


In geometry, two lines or planes are said to be perpendicular if they intersect at a right angle, which is an angle of degrees.

For example, in the Cartesian coordinate system, the -axis and -axis are perpendicular to each other.

Similarly, the edges of a square or rectangle are perpendicular to each other, as are the faces of a cube or rectangular prism.

The symbol for perpendicularity is ⊥. For example, if you have two lines, and , you can write to mean “line is perpendicular to line ”.

Related Terms


An angle is a measure of rotation or turning and is usually measured in degrees or radians. In geometry, an angle is the figure formed by two rays, sharing a common endpoint called the vertex.



In geometry, the perpendicular symbol is used to show that two lines are perpendicular to each other. Visually, the symbol is made up of two lines that form a perpendicular angle.