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.

British Dictionary definitions for syrtis major

Syrtis Major
/ (ˈsɜːtɪs) /

noun

a conspicuous dark region visible in the N hemisphere of Mars