Big Dipper vs Charles's Wain

Big Dipper and Charles's Wain both are nouns.

Word	Noun	Adjective	Verb	Adverb
Big Dipper	Yes	No	No	No
Charles's Wain	Yes	No	No	No

As nouns, Big Dipper and Charles's Wain are synonyms defined as:

Big Dipper and Charles's Wain: a group of seven bright stars in the constellation Ursa Major

Other synonyms of Big Dipper include Dipper, Plough, Wagon, Wain.

Big Dipper (noun)	Charles's Wain (noun)
a group of seven bright stars in the constellation Ursa Major	a group of seven bright stars in the constellation Ursa Major