acclivity vs ascent

acclivity

noun
  • A slope or inclination of the earth, as the side of a hill, considered as ascending, in opposition to declivity, or descending; an upward slope; ascent. 

ascent

noun
  • The degree of elevation of an object, or the angle it makes with a horizontal line; inclination; gradient; steepness 

  • The act of ascending; a motion upwards. 

  • An increase, for example in popularity or hierarchy 

  • The ascender height in a typeface. 

  • The way or means by which one ascends. 

  • An eminence, hill, or high place. 

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