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

After the deal closes, Masimo is expected to operate as a stand-alone company within Danaher’s Diagnostics segment, alongside other businesses Radiometer, Leica Biosystems, Cepheid and Beckman Coulter Diagnostics, the people familiar with the matter said.

From The Wall Street Journal • Feb. 17, 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

Hubble worked hard, taking images of spiral nebulae every clear night and looking for the telltale variations of Cepheid variables.

From Salon • Feb. 14, 2025

But some astronomers suggested that, moving outward along the "second rung," the cosmic distance ladder might get shaky if the Cepheid measurements become less accurate with distance.

From Science Daily • Mar. 11, 2024

A special type of star, called a Cepheid variable, had a property that allowed Hubble to measure the distance to faraway objects.

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