chasma

Meaning

Noun

• A long, narrow, steep-sided depression on a planet (often other than Earth), a moon, or another body in the Solar System.
• An aurora.

Origin

• From Latin chasma, from Ancient Greek χάσμα ("abyss, cleft"), from Ancient Greek χᾰ́σκω ("to gape, yawn") (possibly from Proto-Indo-European *ǵʰan-, *gʰan- + -σκω, from Proto-Indo-European *-sḱéti ("suffix forming a durative or iterative [[imperfective aspect"); or from Proto-Indo-European *ǵʰeh₁y- ("to gape, yawn")) + Ancient Greek -μᾰ ("suffix forming a noun denoting the result of an action") (from Proto-Indo-European *-mn̥ ("suffix forming an [[action noun")).
• The obsolete “aurora” sense is from the fact that aurorae were thought to be rifts in the sky from which light shone through: see the 1822 quotation.