Officially the Plough, (Big Dipper, Charles' Wain) is an asterism, not a constellation. It's a notable grouping of stars within a constellation. The constellation is Ursa Major. However, the Plough is my favourite asterism or constellation as it was the first one I learnt to recognise nearly 50 years ago. Plus it's a pointer to a number of other bright stars, not just Polaris.