A line is essentially a series of points. In algebra, if you have two points you can draw a line. A line can be defined, with a starting point and ending point, or it can be infinite (in algebraic terms), heading off in one or two directions without end. In the latter case, it is also directional, pointing up, down, left, right, or in a diagonal. An implied line may not be solid, but still lead you (physically or visually) in a linear fashion toward a location.
|Image credit: Kleinman, Susan. "Mid-Country Modern." Metropolitan Home. April 2006. 98. (Overlay mine.)|