Cepheid

American  

[see-fee-id, sef-ee-id] / ˈsi fi ɪd, ˈsɛf i ɪd /

noun

plural

Cepheids

1. Astronomy. Cepheid variable.

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Cepheid Scientific  

/ sē′fē-ĭd,sĕf′ē- /

1. Any of a class of variable stars whose luminosity fluctuates with an extremely regular period. There is a strong correlation between the absolute magnitude of a Cepheid's luminosity and its period. By comparing the apparent magnitude of a Cepheid to the absolute magnitude corresponding to its period, it is possible to determine fairly accurately how distant the Cepheid is from Earth.

2. Also called Cepheid variable

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Example Sentences

Chief Executive Rainer Blair said the company continued on a steady recovery path, with strength in bioprocessing and better-than-expected life sciences results largely offsetting a softer first-quarter respiratory season for its Cepheid unit.

From The Wall Street Journal • Apr. 21, 2026

These include Cepheid variable stars, which brighten and dim in predictable ways, red giant stars with known brightness, Type Ia supernovae, and certain galaxy types.

From Science Daily • Apr. 12, 2026

The Washington, D.C.–based conglomerate makes medical and scientific tools, spanning research to diagnostics, including Covid tests by its Cepheid division—one of the first-approved and widely used versions.

From Barron's • Jan. 8, 2026

She was particularly interested in Cepheid variables, which are stars whose brightness pulses regularly, so they get brighter and dimmer with a particular period.

From Salon • Feb. 14, 2025

Cepheid stars pulsate, getting brighter and dimmer in a very predictable way; the way they pulsate is closely related to how much light they put out.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife