Pronunciation: (ûrth),[key] —n. 1. (often cap.) the planet third in order from the sun, having an equatorial diameter of 7926 mi. (12,755 km) and a polar diameter of 7900 mi. (12,714 km), a mean distance from the sun of 92.9 million mi. (149.6 million km), and a period of revolution of 365.26 days, and having one satellite. See table under planet. 2. the inhabitants of this planet, esp. the human inhabitants: The whole earth rejoiced. 3. this planet as the habitation of humans, often in contrast to heaven and hell: to create a hell on earth. 4. the surface of this planet: to fall to earth. 5. the solid matter of this planet; dry land; ground.
6. soil and dirt, as distinguished from rock and sand; the softer part of the land.
7. the hole of a burrowing animal; lair.
8. Chem.any of several metallic oxides that are difficult to reduce, as alumina, zirconia, and yttria. Cf. alkaline earth, rare earth. 9. Also called earth' col"or.Fine Arts.any of various pigments consisting chiefly of iron oxides and tending toward brown in hue.
10. Chiefly Brit. Elect.a ground.
11. Archaic.a land or country.
12. move heaven and earth. See heaven (def. 7).
13. on earth, in the world: Where on earth have you been? 14. run to earth, a. Hunting.to chase (an animal) into its hole or burrow: to run a fox to earth. b. to search out; track down: They ran the fugitive to earth in Algiers.