Olympus Mons


noun
  1. the highest of the giant shield volcanoes on Mars, lying 18°N of the equator. Height: 26 km; base diameter: over 600 km

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012