plural of crater of eternal darkness

(space science) A crater or other depression, on a solid, non-luminous celestial body, the interior of which contains one or more points which lie in perpetual shadow due to a combination of high latitude and being on a celestial body with low axial tilt.

(space science) A mountain peak, on a solid, non-luminous celestial body, which experiences continuous or near-continuous illumination due to a combination of high altitude, very high latitude, and being on a celestial body with very low axial tilt.