During the Civil War, slaves escaping the South through the network of safe havens known as the underground railroad, referred to the Dipper as the Drinking Gourd. Its location is always found in the northern part of the sky, so the Drinking Gourd made an easy marker to follow as blacks made their way north to freedom. The Dipper is really an asterism, a group of stars which form a picture, but which has not been officially recognized by professional astronomers as a constellation. Ursa Major, the Great Bear, is the official name of the constellation which Americans refer to as the Big Dipper. The Great Bear is difficult to see from urban locations, so the Big Dipper has continued to remain more popular in this country than the official constellation.
Constellations are very much like states with official borders.
Within these boundaries certain stars may be found to form a picture, but all stars within the boundary are considered members of the constellation. There is no official strategy with regards to how the stars of a particular constellation are to be connected to form a picture. Constellations are useful to modern astronomy because they allow an approximate location for knowing where objects in the sky can be found. The principal star, Alpha, is really a double star with its secondary component, Proxima, on the sunward side of its orbit. Therefore, technically, Proxima is the closest star to our sun.