Uranus

American  

[yoor-uh-nuhs, yoo-rey-] / ˈyʊər ə nəs, yʊˈreɪ- /

noun

1. Astronomy. the planet seventh in order from the sun, having an equatorial diameter of 32,600 miles (56,460 km), a mean distance from the sun of 1,784 million miles (2,871 million km), a period of revolution of 84.07 years, and 15 moons.

2. Classical Mythology. Also the personification of Heaven and ruler of the world, son and husband of Gaia (Earth) and father of the Titans, who was castrated and dethroned by his youngest son, Cronus, at the instigation of Gaia.

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Uranus ¹ British  

/ ˈjʊrənəs, jʊˈreɪnəs /

noun

1. one of the giant planets, the seventh planet from the sun, sometimes visible to the naked eye. It has 27 satellites, a ring system, and an axis of rotation almost lying in the plane of the orbit. Mean distance from sun: 2870 million km; period of revolution around sun: 84 years; period of axial rotation: 17.23 hours; diameter and mass: 4 and 14.5 times that of earth respectively

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Uranus ² British  

/ jʊˈreɪnəs, ˈjʊrənəs /

noun

1. Greek myth the personification of the sky, who, as a god, ruled the universe and fathered the Titans and Cyclopes on his wife and mother Gaea (earth). He was overthrown by his son Cronus

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Uranus Scientific  

/ yr′ə-nəs,y-rā′- /

1. The seventh planet from the Sun and the third largest, with a diameter about four times that of Earth. Though slightly larger than Nepture, Uranus is the least massive of the four gas giants and is the only one with no internal heat source. A cloud layer of frozen methane gives it a faint bluish-green color, and it is encircled by a thin system of 11 rings and 27 moons. Uranus's axis is tilted 98° from the vertical—the greatest such tilt in the solar system—with the result that its poles are in continuous darkness or continuous sunlight for nearly half of its 84-year orbital period.

2. See Table at solar system

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Uranus Cultural  

1. In astronomy, the seventh major planet from the sun, named for the Greek god of the sky. Uranus was the first planet discovered in modern times (1781). (See solar system.)

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Etymology

Origin of Uranus

From Latin Ūranus, from Greek Ouranós; Uranus def. 2 was first recorded in 1700–10, and Uranus def. 1 in 1780–85

Example Sentences

Neither Uranus nor Neptune has ever hosted an orbiter or long-term mission, making them the only planets in the solar system that have not been closely examined over time.

From Science Daily • Apr. 3, 2026

Reaching Uranus is difficult primarily because of its extreme distance.

From Science Daily • Apr. 3, 2026

On larger icy moons such as Titania, another moon of Uranus, the drop in pressure caused by melting would likely crack the ice shell before reaching the triple point for water, the team found.

From Science Daily • Mar. 2, 2026

Higher in the sky, Uranus will be sitting in the constellation Taurus and won't set until around midnight giving skywatchers with the right equipment a better chance of tracking it down.

From BBC • Feb. 27, 2026

His “Cosmic Mystery” was disproved entirely by the much later discoveries of the planets Uranus, Neptune and Pluto—there are no additional platonic solids' that would determine their distances from the sun.

From "Cosmos" by Carl Sagan

Related Words

• earth