dilatation vs elongation

dilatation

noun
  • The act of dilating; expansion; an enlarging on all sides; the state of being dilated 

  • Prolixity; diffuse discourse. 

  • A dilation or enlargement of a canal or other organ. 

elongation

noun
  • the state of being lengthened 

  • The act of lengthening 

  • The ratio of the extension of a material to the length of the material prior to stretching. 

  • Removal to a distance; withdrawal; a being at a distance; distance. 

  • The angular distance of a planet from the sun 

  • That which lengthens out; continuation. 

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