The Big Dipper (US) or the Plough (UK) is an asterism consisting of seven bright stars of the constellation Ursa Major; six of them are of second magnitude and one, Megrez (δ), of third magnitude. Four define a "bowl" or "body" and three define a "handle" or "head". It is recognized as a distinct grouping in many cultures.
The North Star (Polaris), the current northern pole star and the tip of the handle of the Little Dipper, can be located by extending an imaginary line through the front two stars of the asterism, Merak (β) and Dubhe (α). This makes it useful in celestial navigation.
The constellation of Ursa Major has been seen as a bear, a wagon, or a ladle. The "bear" tradition is Greek, but apparently the name "bear" has parallels in Siberian or North American traditions.
The name "Bear" is Homeric, and apparently native to Greece, while the "Wain" tradition is Mesopotamian. Book XVIII of Homer's Iliad mentions it as "the Bear, which men also call the Wain". In Latin, these seven stars were known as the "Seven Oxen" (septentriones, from septem triōnēs). The classical mythographer identified the "Bear" as the nymph Callisto, changed into a she-bear by Hera, the jealous wife of Zeus.
In Ireland and the United Kingdom, this pattern is known as the Plough. The symbol of the Starry Plough has been used as a political symbol by Irish Republican and left wing movements. Former names include the Great Wain (i.e., wagon) or Butcher's Cleaver. The terms Charles's Wain and Charles his Wain are derived from the still older Carlswæn. A folk etymology holds that this derived from Charlemagne, but the name is common to all the Germanic languages and intended the churls' wagon (i.e., "the men's wagon"), in contrast with the women's wagon (the Little Dipper). An older "Odin's Wain" may have preceded these Nordic designations.