Milky Way

American  

[mil-kee wey] / ˈmɪl ki ˈweɪ /

noun

Astronomy.

1. the spiral galaxy containing our solar system: with the naked eye it appears as a faint luminous band stretching across the heavens, composed of approximately a trillion stars, most of which are too distant to be seen individually.

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Milky Way British  

noun

1. the diffuse band of light stretching across the night sky that consists of millions of faint stars, nebulae, etc, within our Galaxy

2. another name for the Galaxy

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Milky Way Scientific  

/ mĭl′kē /

1. The spiral galaxy that contains our solar system. Made up of an estimated two hundred billion stars or more, it is seen from Earth as an irregular band of hazy light across the night sky. The solar system is located in one of the revolving spiral arms, about 50 light-years north of the galactic plane and some 27,700 light-years from the galaxy's center, which lies in the direction of the constellation Sagittarius. It takes approximately 250 million years for the solar system to orbit the galactic center, which is believed to contain a massive black hole. The Milky Way measures about 100,000 light-years in diameter and is the second largest galaxy, after the Andromeda Galaxy, in the cluster known as the Local Group.

2. See also spiral galaxy

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Milky Way Cultural  

1. The galaxy to which our sun belongs.

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Discover More

The Milky Way is also the swath of light in the night sky produced by the other stars in the galaxy.

Etymology

Origin of Milky Way

First recorded in 1350–1400; Middle English, translation of Latin via lactea; cf. galaxy

Example Sentences

NASA's Kepler mission transformed exoplanet science by monitoring roughly 100,000 stars and demonstrating that planets are extraordinarily common throughout the Milky Way.

From Science Daily • Jun. 1, 2026

Roman, however, will search largely unexplored areas of the Milky Way, offering a much broader view of planetary systems across our galaxy.

From Science Daily • Jun. 1, 2026

Its galactic bulge survey alone will observe approximately 100 million stars while exploring regions of the Milky Way that remain largely uncharted.

From Science Daily • Jun. 1, 2026

By examining entirely different populations of stars and planets across the Milky Way, Roman could greatly expand these studies and help reveal how common planetary systems like our own really are.

From Science Daily • Jun. 1, 2026

Some people think the Milky Way is a long line of stars, but it isn’t.

From "The Curious Incident of the Dog in the Night-Time" by Mark Haddon