Sentence:  The most prominent tectonic feature on Tethys is the globe-girdling Ithaca <WSD>Chasma</WSD>, which is 60 to 100 km wide, 3–4 km deep, and can be traced through at least 270° of a rough great circle (Smith et al, 1982; Moore & Ahern, 1983). ... Odysseys Tangent <WSD>Chasma</WSD>. A prominent <WSD>chasma</WSD> 60–80 km wide and at least 800 km long (90° arc), visible in 80.27, is tangent to the rim of w:Odysseus (crater) 
Meaning of the word marked with <WSD> tags:  A long, narrow, steep-sided depression on a planet (often other than Earth), a moon, or another body in the Solar System.