### What does that really mean?

**More on straight**: Lines must be straight or they would look like this.

**Dots**: A line is made up by so many dots that when we draw the line, we make it solid. However, keep in mind that it's just an infinite number of dots.

**Showing infinity**: We use arrows on the tips of the line to show that the line continues forever.

Unlike a line, a ray has one endpoint and continues forever in only one direction.

Unlike a line, a segment has two endpoints.