[ yoor-uh-nuhs, yoo-rey- ]

  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. Also Ouranos. Classical Mythology. 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.

Origin of Uranus

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

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British Dictionary definitions for Uranus (1 of 2)


/ (jʊˈreɪnəs, ˈjʊrənəs) /

  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

British Dictionary definitions for Uranus (2 of 2)


/ (jʊˈreɪnəs, ˈjʊrənəs) /

  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

Origin of Uranus

C19: from Latin Ūranus, from Greek Ouranos heaven

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for Uranus


[ yurə-nəs, yu-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. See Table at solar system.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for Uranus


[ (yoor-uh-nuhs, yoo-ray-nuhs) ]

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.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.