We don't have synonyms for sevan yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are seven, sedan and sivan.
(n) :
formerly an island in the northwestern part of Lake Sevan in Armenia, which was transformed into a peninsula after the artificial draining during the Soviet era
(n) :
formerly an island in the northwestern part of Lake Sevan in Armenia, which was transformed into a peninsula after the artificial draining during the Soviet era