The angle of sail is the difference between the direction your boat is heading and the direction of the wind. Different angles of sail, called points of sail, change as your boat changes course, and the sails must be adjusted to harness the wind as efficiently as possible. When sailing as close to the wind as possible, with the sails trimmed in all the way, you are close-hauled or beating. As you bear off, steering away from the wind, you will ease your sails as you sail onto a close reach, then a beam reach (where the wind is blowing over the side, or beam, of your boat), then a broad reach.
When you are sailing directly away from the wind, you are sailing on a run with your sails eased all the way out. If you continue to turn, you will gybe, so that you are on a run with your sails on the opposite side of the boat. As you gradually head up, turning toward the wind, you will need to trim your sails to keep them from luffing (flapping in the wind) as you sail onto a broad reach, then a beam reach, close reach, and finally back up to close-hauled.