aa vs lava

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. 

lava

noun
  • A shade of red, named after the volcanic lava. 

  • The molten rock ejected by a volcano from its crater or fissured sides. 

  • Magma. 

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