aa vs magma

aa

noun
  • A form of lava flow associated with Hawaiian-type volcanoes, consisting of basaltic rock, usually dark-colored with a jagged and loose, clinkery surface. Compare pahoehoe. 

magma

noun
  • The molten matter within the earth, the source of the material of lava flows, dikes of eruptive rocks, etc. 

  • The residuum after expressing the juice from fruits. 

  • A basic algebraic structure consisting of a set equipped with a single binary operation. 

  • Any soft doughy mass. 

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