basement vs ground level

basement

noun
  • A floor of a building below ground level. 

  • Last place in a sports conference standings. 

  • A mass of igneous or metamorphic rock forming the foundation over which a platform of sedimentary rocks is laid. 

ground level

noun
  • Ground floor (of a building) 

  • The level of the ground, the surface of the earth. 

  • Ground state, the stationary state of lowest energy of a particle. 

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