Pronunciation: (sat'urn),[key] —n. 1. an ancient Roman god of agriculture, the consort of Ops, believed to have ruled the earth during an age of happiness and virtue, identified with the Greek god Cronus.
2. Astron.the planet sixth in order from the sun, having an equatorial diameter of 74,600 mi. (120,000 km), a mean distance from the sun of 886.7 million mi. (1427 million km), a period of revolution of 29.46 years, and 21 known moons. It is the second largest planet in the solar system, encompassed by a series of thin, flat rings composed of small particles of ice. See table under planet. 3. Alchemy.the metal lead.
4. a U.S. space-vehicle booster developing from 2 million to 9 million lb. (900,000 to 4 million kg) of thrust for launching satellites, probes, and spaceships.