“Point of sail” refers to the angle of the sailboat to the direction from which the wind is blowing. Different terms are used for the different points of sail, and the sails must be trimmed into different positions for different points of sail.
Consider this diagram, which shows the basic points of sail for different boat directions relative to the wind. Here, the wind is blowing from the top of the diagram (think of it as north). A sailboat sailing close to the wind on either side (toward the northwest or northeast) is close hauled. Sailing directly across the wind (due west or due east) is called a beam reach. Off the wind (to the southwest or southeast) is called a broad reach. Directly downwind (due south) is called running.
Next we’ll look at each of these points of sail and how the sails are trimmed for each.