buttock vs transom

buttock

noun
  • The convexity of a ship behind, under the stern. 

  • Each of the two large fleshy halves of the posterior part of the body between the base of the back, the perineum and the top of the legs. 

transom

noun
  • The flat or nearly flat stern of a boat or ship. 

  • The horizontal beam on a cross or gallows. 

  • A crosspiece over a door; a lintel. 

  • Any of several transverse structural members in a ship, especially at the stern; a thwart. 

  • Items that have arrived over the transom. 

  • A transom window. 

  • A horizontal dividing bar in a window. 

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