Cassiopeia

American  

[kas-ee-uh-pee-uh] / ˌkæs i əˈpi ə /

noun

1. Astronomy. a northern constellation between Cepheus and Perseus.

2. Classical Mythology. the wife of Cepheus and mother of Andromeda.

---

Cassiopeia ¹ British  

/ ˌkæsɪəˈpiːə /

noun

1. a very conspicuous W-shaped constellation near the Pole Star. Cassiopeia A is a very strong radio and X-ray source, identified as the remnant of a supernova thought to have occurred in the late 17th century

---

Cassiopeia ² British  

/ ˌkæsɪəˈpiːə /

noun

1. Greek myth the wife of Cepheus and mother of Andromeda

---

Cassiopeia Scientific  

/ kăs′ē-ə-pē′ə /

1. A W-shaped constellation in the Northern Hemisphere near Andromeda and Cepheus.

---

Other Word Forms

• Cassiopeian
  adjective

Example Sentences

After collecting the data from Cassiopeia A, they compared the measured amounts of chlorine and potassium with several theoretical models of how supernovae create elements.

From Science Daily • Dec. 8, 2025

From the ground, Apophis will resemble a star traversing the night sky, as bright as the constellation Cassiopeia and slower than a satellite.

From Los Angeles Times • Feb. 14, 2023

It's a special type of neutron star, called a magnetar, located approximately 13,000 lightyears from Earth in the constellation Cassiopeia.

From Salon • Jan. 9, 2023

SEI is working on a project called Cassiopeia, which plans to place a constellation of very large satellites in a high Earth orbit.

From BBC • Oct. 31, 2022

Not to be outdone, Cassiopeia stood on the seat and waved her book in the air.

From "The Interrupted Tale" by Maryrose Wood