Syrtis Major

[ sur-tis ]
/ ˈsɜr tɪs /

noun

an area in the northern hemisphere and near the equator of Mars, appearing as a dark region when viewed telescopically from the earth.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for syrtis major

Syrtis Major

/ (ˈsɜːtɪs) /

noun

a conspicuous dark region visible in the N hemisphere of Mars
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