We don't have synonyms for sundon yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are sundown, sundog and sindon.
(n) :
A civil parish in Central Bedfordshire district, Bedfordshire, England, in which the villages of Upper Sundon and Lower Sundon are located (OS grid ref TL0427).
(n) :
A civil parish in Central Bedfordshire district, Bedfordshire, England, in which the villages of Upper Sundon and Lower Sundon are located (OS grid ref TL0427).