Cytherean

Cytherean is an adjective meaning pertaining to Cythera (Greek Κύθηρα, also transliterated Kythera or Kithira), a small island now part of Greece, southeast of the Peloponnesus. It is also an adjective meaning pertaining to the planet Venus.

When planetary scientists began to have a need to discuss Venus in detail, an adjective was needed. Based on Latin principles, the correct adjectival form of the name would be Venerean. However, this term has an unfortunate similarity to the word venereal as in venereal diseases (related to "Venerean" as martial is to "Martian"), and is not generally used by astronomers. The term Venusian is etymologically messy (similar to saying "Earthian" or "Jupiterian"), and a "cleaner" version was desired.