- 1 Roman Mythology the god of war and the most important Roman god after Jupiter. The month of March is named after him. Greek equivalent Ares.
- 2 Astronomy a small, reddish planet that is the fourth in order from the sun and is periodically visible to the naked eye.
Mars orbits between earth and Jupiter at an average distance of 141.6 million miles (228 million km) from the sun, and has an equatorial diameter of 4,208 miles (6,787 km). Its characteristic red color arises from the iron-rich minerals covering its surface. There is a tenuous atmosphere of carbon dioxide, and the seasonal polar caps are mainly of frozen carbon dioxide. Unambiguous evidence of life has yet to be found. There are two small satellites, Phobos and Deimos