Arcturus

American  

[ahrk-toor-uhs, -tyoor-] / ɑrkˈtʊər əs, -ˈtyʊər- /

noun

Astronomy.

1. a first-magnitude star in the constellation Boötes.

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Arcturus British  

/ ɑːkˈtjʊərəs /

noun

1. the brightest star in the constellation Boötes: a red giant. Visual magnitude: –0.4; spectral type: K2III; distance: 37 light years

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Arcturus Scientific  

/ ärk-tr′əs /

1. A giant star in the constellation Boötes. It is the brightest star in the Northern Hemisphere and the fourth brightest star in the sky, with an apparent magnitude of 0.00. Scientific name: Alpha Boötes.

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Other Word Forms

Derived Forms

• Arcturian
  adjective

Etymology

Origin of Arcturus

1352–75; < Latin < Greek Arktoûros, equivalent to árkt ( os ) bear + -oûros keeper; replacing Middle English arture < Middle French

Example Sentences

Nor do they usually follow a “prophet” who claims to have come from the star Arcturus.

From The Wall Street Journal • May 28, 2026

To find the area of sky where it should appear, she advises to first locate the plough and follow its handle to Arcturus.

From BBC • Dec. 30, 2024

XBB 1.16, the dominant Omicron subvariant dubbed Arcturus, has been manifesting as pinkeye.

From Los Angeles Times • Jul. 28, 2023

Meanwhile, Arcturus has jumped to around 12.5 percent of cases, a rise from just 1 percent at the end of March.

From Salon • May 16, 2023

The three, Denebola, Spica, and Arcturus, mark the corners of a great equilateral triangle.

From Astronomy with an Opera-glass A Popular Introduction to the Study of the Starry Heavens with the Simplest of Optical Instruments by Serviss, Garrett Putman