Definition 1: (1) The Roman god of war, of husbandry, shepherds and seers. (2) The "red" planet, the fourth from the sun, revolving around it every 687 days at a distance of 227.9 million kilometers (141.6 million miles) and with a diameter of 6,794 kilometers (4,222 miles).

Usage 1: August 27 Earth and Mars passed within 55,760,000 kilometers (34,649,264 miles) of each other—closer than at any time in the past 60,000 years. The adjective, "Martian," is also used as a noun to refer to inhabitants of Mars. Is there life on Mars? According to popular Russian graffiti of the 70s, "No, not there either."

Suggested usage: In Chaucer's Canterbury Tales, the Wife of Bath makes a comparison of Mars and Venus similar to the one that has recently reemerged in English arm-chair psychology: "Venus me yaf [gave] my lust, my likerousnesse [wantonness], And Mars yaf [gave] me my sturdy hardinesse." Mars' lover in Roman mythology was Venus, which is why Mardian says in Shakespeare's Anthony and Cleopatra, "Yet have I fierce affections, and think What Venus did with Mars."

Etymology: Like the other planets, Mars is named for a Roman god, Mars. Mars was the father of Romulus, the mythical father of the Roman people, thus the progenitor of the Roman Empire. The month of Martius "March," the beginning of the Roman year, was named for him probably because it was the usual time to plant crops and launch military campaigns (see Definition). The original root is *mar- "gleam," found in Sanskrit marikis "beam of light," hence the bright god of armor and war, a notion equally befitting a planet. (Today's word was suggested by Nymann of the Agora, where over 1,000 word-lovers share thoughts about their favorite words every day.)