opus vs still life

opus

noun
  • A work, especially of art. 

  • A work of music or set of works with a specified rank in an ordering of a composer's complete published works. 

still life

noun
  • A work of art depicting an arrangement of inanimate objects. 

  • A pattern that does not change from one generation to the next. 

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