A long thin mark made by a pen, pencil, etc.

In geometry a line:

• is straight (no curves),

• has no thickness, and

• extends in both directions without end (infinitely).

If it does have ends it is called a "Line Segment".

Try moving points "A" and "B":

In geometry a line:

• is straight (no curves),

• has no thickness, and

• extends in both directions without end (infinitely).

If it does have ends it is called a "Line Segment".

Try moving points "A" and "B":

See: Line Segment