quahog vs topneck

quahog

noun
  • The largest size of such an edible clam, generally considered only fit for use in chowders and other clam dishes. 

  • An edible clam with a hard shell found along the Atlantic Coast of North America, from species Mercenaria mercenaria, formerly Venus mercenaria. 

  • A similar edible clam found along coasts around the North Atlantic, generally in deeper waters, the ocean quahog, black quahog, mahogany clam or Icelandic cyprine, Arctica islandica 

verb
  • To dig for quahogs. 

topneck

noun
  • A quahog clam that is larger than a littleneck but smaller than a cherrystone. 

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