Geometry beginning with P

Geometry Definitions
Click one of the letters above to go to the page of all terms beginning with that letter.
Parallel Lines

Two lines, both in the same plane, that never intersect.

Parallel lines
Parallel Planes

Two planes that do not intersect.

Perpendicular Lines

Two lines that intersect and form right angles.

Perpendicular lines
Perpendicular Planes

To Be Described.


An infinite set of connected points forming a flat surface. A plane has infinite length, infinite width and zero thickness.

flat plane

A fundamental object in geometry. It is represented by a dot, and named by a capital letter. A point is a location in space and has no size.



A statement that is assumed true with no proof. Examples:

  • A line contains at least 2 points.
  • A plane contains at least 3 non-linear points.

Often referred to as a axiom. The words axiom and postulate may be used interchangably.