selenite /selˈi-nīt/ noun

1. Gypsum, esp in transparent crystals (anciently supposed to wax and wane with the moon)
2. A salt of selenious acid

selenitic /sel-i-nitˈik/ adjective

selenium /si-lēˈ/ noun

A metalloid element (symbol Se; atomic no 34) discovered by Berzelius in 1817 and named from its resemblance to tellurium

selēˈnograph noun

A delineation of the moon

selenographer /sel-i-nogˈrə-fər/ noun

selenographic /si-lē-nə-grafˈik/ or selenographˈical adjective

selenography /sel-i-nogˈrə-fi/ noun

1. Mapping of the moon
2. The study of the moon's physical features

selēnologˈical adjective

selenolˈogist noun

A selenographer

selenolˈogy noun

The scientific study of the moon

selenomorpholˈogy noun

The study of the surface of the moon

selenium cell noun

A photoelectric cell dependent on the circumstance that light increases the electric conductivity of selenium