The earth is the third planet from the sun in the solar system, orbiting between Venus and Mars at an average distance of 90 million miles (149.6 million km) from the sun, and has one natural satellite, the moon. It has an equatorial diameter of 7,654 miles (12,756 km), an average density 5.5 times that of water, and is believed to have formed about 4,600 million years ago. The earth, which is three-quarters covered by oceans and has a dense atmosphere of nitrogen and oxygen, is the only planet known to support life
- 4 ElectricalBritish term for ground1 (sense 7 of the noun).
- 3 ElectricalBritish term for ground1 (sense 5 of the verb).
Old English eorthe, of Germanic origin; related to Dutch aarde and German Erde