pious vs seraph

pious

adj
  • Relating to religion or religious works. 

  • Of or pertaining to piety, exhibiting piety, devout, godfearing. 

  • Insisting on or making a show of one's own virtue, especially in comparison to others; sanctimonious, condescending, judgmental. 

seraph

noun
  • A six-winged angel; one of the highest choir or order of angels in Christian angelology, ranked above cherubim, and below God. They are the 5th-highest order of angels in Jewish angelology. A detailed description can be found at the beginning of Isaiah chapter 6. 

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