The North Node, sometimes called the "Dragon's Head," is a sensitive point where the moon's orbit around the earth rises from below the horizon.
It expresses your dharma, or soul destiny. The Zodiac sign your North Node is in will tell you about the qualities that you must develop within yourself. For example, those with a North Node in Aquarius are devoted to the search for universal truth, holistic living, and open-mindedness.
The natal house containing your North Node indicates the area of life you will need to bring those qualities into. As an example, having the North Node in the 11th house would compel you to work with those around you to help the world be a better place.