stalactite vs stalagmite

stalactite

noun

  • A secondary mineral deposit of calcium carbonate or another mineral, in shapes similar to icicles, that hangs from the roof of a cave. 

  • Coordinate term: stalagmite 

stalagmite

noun

  • A secondary mineral deposit of calcium carbonate or other mineral, in shapes similar to icicles, that lies on the ground of a cave. 

  • Coordinate term: stalactite 

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