firmament

American  

[fur-muh-muhnt] / ˈfɜr mə mənt /

noun

1. the vault of heaven; sky.

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firmament British  

/ ˈfɜːməmənt, ˌfɜːməˈmɛntəl /

noun

1. the expanse of the sky; heavens

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Other Word Forms

• firmamental
  adjective

Etymology

Origin of firmament

1250–1300; Middle English < Late Latin firmāmentum sky, Latin: support, prop, stay, equivalent to firmā ( re ) to strengthen, support ( see firm ²) + -mentum -ment

Explanation

The firmament is the curve of the sky, especially if you imagine it as a solid surface. You can describe the sky at night as a firmament shining with stars (if you're feeling poetic). The word firmament comes from the Latin firmus, or "firm," and this description of the sky as something solid reflects ancient ideas of the way the universe was constructed. The first stargazers imagined the sky as a sphere, and it wasn't until the late 1500s that the idea of an infinite universe was seriously considered. Today the word firmament is mostly literary, used to poetically describe the visual curve of the sky.

Example Sentences

See Examples For:

firmament

It is our fervent belief that this conversation about the role of the court in the U.S. legal firmament will serve to make the court more durable.

From Slate ● Jul. 20, 2026

A century on, the place of all three in the firmament is secure.

From The Wall Street Journal ● Nov. 14, 2025

As for the food, Gold called some of it “ordinary,” but noted, “Weirdly enough, I don’t care,” noting the restaurant’s place in L.A.’s culinary firmament.

From Los Angeles Times ● Aug. 17, 2025

Not all of our stars are onscreen; more than two dozen are in the Michelin firmament.

From Los Angeles Times ● Aug. 8, 2025

He bathed in the fresh cold water at the river’s edge and lay on his back under the sun, trying to fathom the firmament.

From "Abel's Island" by William Steig