Cassiopeia n.

northern circumpolar constellation, in Greek mythology queen of Ethiopia, wife of Cepheus and mother of Andromeda, from Latinized form of Greek Kassiepeia, Kassiopeia, a name of unknown etymology. A conspicuous "W" (or "M") of stars, always opposite the Big Dipper, she is represented as seated in a chair. The supernova there in 1572 outshone Venus, was observed by Tycho, among others, and helped revolutionize astronomy. Related: Cassiopeian.