Basic definitions

Math

Definition

The foundational terms in geometry including point (a location with no size), line (extends infinitely in both directions), plane (a flat surface extending infinitely), and segment (a part of a line with two endpoints). These are the building blocks for all geometric reasoning.

Examples

  • A point is named with a capital letter like point A, a line through two points is written as line AB
  • Two points determine exactly one line, and three non-collinear points determine exactly one plane

Related Terms

Segments and rays Measuring angles Angle pairs Ordered pairs

Study This Concept

Practice basic definitions with free review games in these units:

Geometry Unit 1: Points Lines and Planes