A line is a geometric figure that is defined by a straight path that extends in opposite directions indefinitely. A line has only one dimension which is length.

line m and line AB


We can name a line using a single lowercase letter just like line \(m\) above. Or, we can also name a line using any two points found on the line and by placing a double headed arrow above. If points  A and B are on the line, we can name it as \(\overleftrightarrow{AB}\).