chasma

/K AE1 Z M AH0/
noun
  1. 1

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

  2. 2

    (astronomy, obsolete, rare) An aurora.

  3. 3

    Obsolete form of chasm. [(geology, planetology) A deep, steep-sided rift, gap or fissure; a gorge or abyss.]