gravity vs lightness

gravity

noun
  • The lowness of a note. 

  • The state or condition of being grave; seriousness. 

  • Specific gravity. 

  • The state or condition of having weight; weight; heaviness. 

  • Gravitation, the universal force exercised by two bodies onto each other. 

  • The force at the Earth's surface, of the attraction by the Earth's masses, and the centrifugal pseudo-force caused by the Earth's rotation, resulting from gravitation. 

lightness

noun
  • Levity, frivolity; inconsistency. 

  • The state of having little (or less) weight, or little force. 

  • the relative whiteness or transparency of a colour 

  • Agility of movement. 

  • The product of being illuminated. 

  • Freedom from worry. 

  • the condition of being illuminated 

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