backbeach vs seashore

backbeach

noun
  • The area of beach furthest from the water's edge; the backshore. 

seashore

noun
  • The coastal land bordering a sea or an ocean. 

  • The foreshore, the strip of land between low water and high water. 

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