Named after Merton Edward Davies - American engineer, planetary geodesist (1917-2001).
Davies is approximately 48 km in diameter. It was named in honor of Merton Davies a pioneer in the cartography of planetary bodies. An employee of the Rand Corporation, he assisted NASA in mapping Mars with colleagues Gérard de Vaucouleurs and Harold Masursky and defined the prime meridian of Mars as passing through the crater Airy-0. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.