catacomb vs mastaba

catacomb

noun
  • An underground system of tunnels and chambers with recesses for graves, used (in former times) as a cemetery; a tunnel system used for burying the dead, as in Paris or Ancient Rome. 

mastaba

noun
  • A wide stone bench built into the wall of a house, shop etc. in the Middle East. 

  • A rectangular structure with a flat top and slightly sloping sides, built during Ancient Egyptian times above tombs that were situated on flat land. Mastabas were made of wood, mud bricks, stone, or a combination of these materials. Some are solid structures, while others can contain one or more rooms, sometimes decorated with paintings or inscriptions. 

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