celestial sphere

noun

: an imaginary sphere of infinite radius against which the celestial bodies appear to be projected and of which the apparent dome of the visible sky forms half

Examples of celestial sphere in a Sentence

Recent Examples on the Web

This is the moment when the sun crosses directly above Earth's equator, moving south into the celestial sphere. — Lissette Gonzalez, CBS News, 21 Sep. 2026

The observations cover approximately 19,500 square degrees of the sky—nearly half of the entire celestial sphere. — Prabhat Ranjan Mishra, Interesting Engineering, 10 Sep. 2026

But now, perhaps entranced by Moon Sirens promising a lunar gold rush, or by the prospect of becoming the planet’s first trillionaire with the launch of the SpaceX IPO, the great SpaceX navigator seems to have lost his way in the celestial sphere. — Kevin Holden Platt, Forbes.com, 28 Apr. 2026

Circumpolar stars Astronomers use a common set of reference points to project Earth’s north and south poles, and the equator, onto the celestial sphere, an imaginary sphere encompassing the sky. — Vahe Peroomian, The Conversation, 5 Mar. 2026

Word History

First Known Use

1538, in the meaning defined above

Rhymes for celestial sphere

• charioteer
• ritonavir
• adhere
• ameer
• amir
• appear
• arrear
• astir
• austere
• career
• cashier
• cohere

Kids Definition

celestial sphere

noun

: an imaginary sphere of infinite radius against which the celestial bodies appear to be projected