Gingerbread is a term used to describe a variety of sweet food products, which can range from a soft, moist loaf cake to something close to a ginger biscuit. What they have in common are the predominant flavors of ginger and a tendency to use honey or molasses (treacle) rather than just sugar. They probably also share a common history.
The harder German-style Gingerbread is often used to build gingerbread houses similar to the "witch's house" encountered by Hansel and Gretel. These houses, covered with a variety of candies and icing, are popular Christmas decorations, often built by children with the help of their parents.