Estuary vs Swale

Estuary

name
  • Estuary English 

Swale

name
  • The Swale, a channel between the Isle of Sheppey and the Kentish mainland 

  • A local government district with borough status in Kent, England, created in 1974 with its headquarters in Sittingbourne and named after the channel 

  • A river, a tributary of the Ure in North Yorkshire, England. 

How often have the words Estuary and Swale occurred in a corpus of books? (source: Google Ngram Viewer )