buccal cavity vs roof

buccal cavity

noun
  • The oral cavity, bound by the cheeks of the face, the palate, and the flesh of the mandible, opening onto the mouth and the fauces, and containing the teeth, tongue, gums, and other structures. 

  • The first part of the stomodaeum, lying just within the mouth; its dilator muscles arising on the clypeus, and inserted before the frontal ganglion and its connectives. 

roof

noun
  • The upper part of a cavity. 

  • The external covering at the top of a building. 

  • The top external level of a building. 

  • An overhanging rock wall. 

  • The surface or bed of rock immediately overlying a bed of coal or a flat vein. 

verb
  • To cover or furnish with a roof. 

  • To traverse buildings by walking or climbing across their roofs. 

  • To put into prison, to bird. 

  • To shelter as if under a roof. 

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