Definition of

Line

Line

In common language it is a long thin mark made by a pen, pencil, etc.

In Geometry a line:
• is straight (no bends),
• has no thickness,
• and extends in both directions without end (infinitely).

One end makes it a "Ray", and two ends makes it a "Line Segment".

Try moving points A and B:

../geometry/images/geom-line.js?mode=line