Point:
A point is a way to describe a specific location in space.
A point has no length, width or depth.
It is drawn by placing a single dot at the location you want to specify, and denoted in text with a capital letter.

Line:
A line is a set of continuous points that extend indefinitely in either direction.
A line is identified by naming two points on the line and drawing a line over the letters . Alternatively, a line may be named by using a single lowercase letter (line l).

Plane:
A plane is a set of points that forms a flat surface that has no depth and that extends indefinitely in all directions.
A plane is usually represented as a closed four-sided figure and is named by placing a capital letter at one of the corners.