arciform vs rounded

arciform

adj
  • Having the form of a bow (weapon) 

rounded

adj
  • Made into a circle or sphere. 

  • Complete or balanced. 

  • Pronounced with the lips drawn together. 

  • Ending in a broad arch. 

  • Describing a number that has been changed to its nearest desired value. 

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