rockpile vs sculpture

rockpile

noun
  • A pile of rocks. 

sculpture

noun
  • A three dimensional work of art created by shaping malleable objects and letting them harden or by chipping away pieces from a rock (sculpting). 

  • The three-dimensional ornamentation on the outer surface of a shell. 

  • Works of art created by sculpting, as a group. 

verb
  • To represent something in sculpture. 

  • To change the shape of a land feature by erosion etc. 

  • To fashion something into a three-dimensional figure. 

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