A ray is a defined term because it extends infinitely in
one direction from an endpoint. A line is an infinite series of points in a row
and it does not occupy any space. They are also called one dimensional since
the direction is in one dimension. A point has a location but no specific size.
It can describe a location but you can never determine its actual size. Imagine
the point at the end of the previous sentence. And then imagine it getting
smaller and smaller until it disappears. We can only use a dot to represent the
point.
