The four cardinal directions are north, south, east and west. These are the four main directions on the compass rose, which is a depiction of all the directions seen on a map. They are usually marked with the initials N, S, E and W.
No absolute direction corresponds to any of the relative directions. This is a consequence of the translational invariance of the laws of physics: nature, loosely speaking, behaves the same no matter what direction one moves.
The terms vertical and horizontal often describe directions: a vertical line goes up and down, and a horizontal line goes across. You can remember which direction is vertical by the letter, "v," which points down.